css-fonts/Fonts.html

Fri, 07 Jun 2013 00:17:45 -0700

author
Peter Linss <peter.linss@hp.com>
date
Fri, 07 Jun 2013 00:17:45 -0700
changeset 8369
660486acf1ee
parent 8368
a0a0866f3b1f
child 8385
c08eb03dc645
permissions
-rw-r--r--

add test annotations to css-fonts-3

     1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
     2 "http://www.w3.org/TR/html4/strict.dtd">
     4 <html lang=en>
     5  <head><meta content="text/html;charset=utf-8" http-equiv=Content-Type>
     7   <title>CSS Fonts Module Level 3</title>
     8   <!--
     9       FIXME when publishing: copy the current default.css and link to
    10       "default.css" rather than "../default.css"
    11    -->
    12   <link href="../default.css" rel=stylesheet type="text/css">
    13   <link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
    14   <!-- I'm just experimenting here, don't get your bee in a bonnet -->
    15   <script src="http://use.typekit.com/xon2bky.js"
    16   type="text/javascript"></script>
    17   <script type="text/javascript">try{Typekit.load();}catch(e){}</script>
    19   <style type="text/css">
    21   body, th, td, h1, h2, h3, h4, h5, h6 {
    22     font-family: "myriad-pro", sans-serif !important;
    23   }
    25   body {
    26     padding: 2em 70px 2em 70px;
    27   }
    29   p + p, p.mtb {
    30     margin-top: 0.8em;
    31     text-indent: 0px;
    32   }
    34   #bolderlighter {
    35     width: 40%;
    36   }
    38   #bolderlighter th {
    39     text-align: center;
    40   }
    42   #fontformats td, #eventhandlers td, #fontformats th, #eventhandlers th {
    43     padding-right: 2em;
    44     text-align: left;
    45   }
    47   dd {
    48     margin-bottom: 1em;
    49   }
    51   #authors dd {
    52     margin-bottom: 0;
    53   }
    55   #fontstylematchingalg {
    56     list-style-type: lower-alpha;
    57   }
    59   #fontmatchingalg ul, #fontmatchingalg ol {
    60     margin-top: 0.8em;
    61   }
    63   #fontmatchingalg li + li {
    64     margin-top: 0.8em;
    65   }
    67   div.example {
    68     padding: 1em;
    69     margin-top: 1em;
    70   }
    72   div.example + div.example {
    73     margin-top: 2em;
    74   }
    76   div.figure {
    77     page-break-inside: avoid;
    78   }
    80   pre.prod { white-space: pre-wrap; margin: 1em 0 1em 2em }
    82   div.featex {
    83     width: 700px;
    84   }
    86   div.featex img {
    87     margin: auto;
    88     display: block;
    89   }
    91   span.tag {
    92     font-family: monospace;
    93     font-size: 120%;
    94   }
    96   ol ol {
    97     list-style-type: lower-alpha;
    98   }
   100   .idl-code {
   101     font-weight: bold;
   102     color: #c50;
   103   }
   104   </style>
   105   <link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
   106   type="text/css">
   107   <script defer=defer
   108     src="http://test.csswg.org/harness/annotate.js#CSS3-FONTS_DEV"
   109     type="text/javascript"></script>
   111  <body>
   112   <div class=head> <!--begin-logo-->
   113    <p><a href="http://www.w3.org/"><img alt=W3C height=48
   114     src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
   116    <h1>CSS Fonts Module Level 3</h1>
   118    <h2 class="no-num no-toc" id=editors-draft-7-june-2013>Editor's Draft 7
   119     June 2013</h2>
   121    <dl id=authors>
   122     <dt>This version:
   124     <dd><a
   125      href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>
   126      <!-- <dd><a href="http://www.w3.org/TR/2013/ED-css3-fonts-20130607/">http://www.w3.org/TR/2013/ED-css3-fonts-20130607/</a> -->
   129     <dt>Latest version:
   131     <dd><a
   132      href="http://www.w3.org/TR/css3-fonts/">http://www.w3.org/TR/css3-fonts/</a>
   134     <dt>Latest editor's draft:
   136     <dd><a
   137      href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>
   138      (<a
   139      href="https://dvcs.w3.org/hg/csswg/log/tip/css-fonts/Fonts.html">change
   140      log</a>)
   142     <dt>Previous version:
   144     <dd><a
   145      href="http://www.w3.org/TR/2013/WD-css3-fonts-20130212/">http://www.w3.org/TR/2013/WD-css3-fonts-20130212/</a>
   147     <dt>Issues List:
   149     <dd><a href="http://www.w3.org/Style/CSS/Tracker/products/18">CSS3 Fonts
   150      issues in Tracker</a>
   152     <dd><a
   153      href="https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&amp;product=CSS&amp;component=Fonts&amp;bug_status=NEW&amp;bug_status=ASSIGNED&amp;bug_status=REOPENED">CSS3
   154      Fonts issues in Bugzilla</a>
   156     <dt>Discussion:
   158     <dd><a
   159      href="mailto:www-style@w3.org?subject=%5Bcss-fonts%5D%20feedback">www-style@w3.org</a>
   160      with subject line “<kbd>[css-fonts] <var>… message topic
   161      …</var></kbd>” (<a
   162      href="http://lists.w3.org/Archives/Public/www-style/"
   163      rel=discussion>archives</a>)
   165     <dt>Editor:
   167     <dd><a href="mailto:jdaggett@mozilla.com">John Daggett (Mozilla)</a>
   168    </dl>
   169    <!--begin-copyright-->
   170    <p class=copyright><a
   171     href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
   172     rel=license>Copyright</a> © 2013 <a href="http://www.w3.org/"><abbr
   173     title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a
   174     href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of
   175     Technology">MIT</abbr></a>, <a href="http://www.ercim.eu/"><abbr
   176     title="European Research Consortium for Informatics and
   177     Mathematics">ERCIM</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>,
   178     <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved. W3C
   179     <a
   180     href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
   181     <a
   182     href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
   183     and <a
   184     href="http://www.w3.org/Consortium/Legal/copyright-documents">document
   185     use</a> rules apply.</p>
   186    <!--end-copyright-->
   187    <hr title="Separator for header">
   188   </div>
   190   <h2 class="no-num no-toc" id=abstract>Abstract</h2>
   192   <p>This CSS3 module describes how font properties are specified and how
   193    font resources are loaded dynamically. The contents of this specification
   194    are a consolidation of content previously divided into <a
   195    href="http://www.w3.org/TR/2002/WD-css3-fonts-20020802/">CSS3 Fonts</a>
   196    and <a href="http://www.w3.org/TR/2002/WD-css3-webfonts-20020802/">CSS3
   197    Web Fonts</a> modules. The description of font load events was moved into
   198    the <a href="http://dev.w3.org/csswg/css3-font-load-events/">CSS3 Font
   199    Load Events</a> module.
   201   <h2 class="no-num no-toc" id=status>Status of this document</h2>
   202   <!--begin-status-->
   204   <p>This is a public copy of the editors' draft. It is provided for
   205    discussion only and may change at any moment. Its publication here does
   206    not imply endorsement of its contents by W3C. Don't cite this document
   207    other than as work in progress.
   209   <p>The (<a
   210    href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
   211    mailing list <a
   212    href="mailto:www-style@w3.org?Subject=%5Bcss3-fonts%5D%20PUT%20SUBJECT%20HERE">
   213    www-style@w3.org</a> (see <a
   214    href="http://www.w3.org/Mail/Request">instructions</a>) is preferred for
   215    discussion of this specification. When sending e-mail, please put the text
   216    “css3-fonts” in the subject, preferably like this:
   217    “[<!---->css3-fonts<!---->] <em>…summary of comment…</em>”
   219   <p>This document was produced by the <a
   220    href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
   221    the <a href="http://www.w3.org/Style/">Style Activity</a>).
   223   <p>This document was produced by a group operating under the <a
   224    href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
   225    2004 W3C Patent Policy</a>. W3C maintains a <a
   226    href="http://www.w3.org/2004/01/pp-impl/32061/status"
   227    rel=disclosure>public list of any patent disclosures</a> made in
   228    connection with the deliverables of the group; that page also includes
   229    instructions for disclosing a patent. An individual who has actual
   230    knowledge of a patent which the individual believes contains <a
   231    href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
   232    Claim(s)</a> must disclose the information in accordance with <a
   233    href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
   234    6 of the W3C Patent Policy</a>.</p>
   235   <!--end-status-->
   236   <!--
   237 <h3 class="no-num no-toc" id="atrisk">Features at risk</h3>
   239 <p>The following features are at risk and may be removed when exiting CR:</p>
   241 <ul>
   242 </ul>
   243 -->
   245   <h2 class="no-num no-toc" id=contents>Table of contents</h2>
   246   <!--begin-toc-->
   248   <ul class=toc>
   249    <li><a href="#introduction"><span class=secno>1 </span>Introduction</a>
   251    <li><a href="#typography-background"><span class=secno>2 </span>Typography
   252     Background</a>
   254    <li><a href="#basic-font-props"><span class=secno>3 </span>Basic Font
   255     Properties</a>
   256     <ul class=toc>
   257      <li><a href="#font-family-prop"><span class=secno>3.1 </span>Font
   258       family: the font-family property</a>
   259       <ul class=toc>
   260        <li><a href="#generic-font-families"><span class=secno>3.1.1
   261         </span>Generic font families</a>
   262       </ul>
   264      <li><a href="#font-weight-prop"><span class=secno>3.2 </span>Font
   265       weight: the font-weight property</a>
   267      <li><a href="#font-stretch-prop"><span class=secno>3.3 </span>Font
   268       width: the font-stretch property</a>
   270      <li><a href="#font-style-prop"><span class=secno>3.4 </span>Font style:
   271       the font-style property</a>
   273      <li><a href="#font-size-prop"><span class=secno>3.5 </span>Font size:
   274       the font-size property</a>
   276      <li><a href="#font-size-adjust-prop"><span class=secno>3.6
   277       </span>Relative sizing: the font-size-adjust property</a>
   279      <li><a href="#font-prop"><span class=secno>3.7 </span>Shorthand font
   280       property: the font property</a>
   282      <li><a href="#font-synthesis-prop"><span class=secno>3.8
   283       </span>Controlling synthetic faces: the font-synthesis property</a>
   284     </ul>
   286    <li><a href="#font-resources"><span class=secno>4 </span>Font
   287     Resources</a>
   288     <ul class=toc>
   289      <li><a href="#font-face-rule"><span class=secno>4.1 </span>The
   290       <code>@font-face</code> rule</a>
   292      <li><a href="#font-family-desc"><span class=secno>4.2 </span>Font
   293       family: the font-family descriptor</a>
   295      <li><a href="#src-desc"><span class=secno>4.3 </span>Font reference: the
   296       src descriptor</a>
   298      <li><a href="#font-prop-desc"><span class=secno>4.4 </span>Font property
   299       descriptors: the font-style, font-weight, font-stretch descriptors</a>
   301      <li><a href="#unicode-range-desc"><span class=secno>4.5 </span>Character
   302       range: the unicode-range descriptor</a>
   304      <li><a href="#composite-fonts"><span class=secno>4.6 </span>Using
   305       character ranges to define composite fonts</a>
   307      <li><a href="#font-rend-desc"><span class=secno>4.7 </span>Font
   308       features: the font-variant and font-feature-settings descriptors</a>
   310      <li><a href="#font-face-loading"><span class=secno>4.8 </span>Font
   311       loading guidelines</a>
   313      <li><a href="#same-origin-restriction"><span class=secno>4.9
   314       </span>Same-origin restriction for fonts</a>
   315       <ul class=toc>
   316        <li><a href="#default-same-origin-restriction"><span class=secno>4.9.1
   317         </span>Default same-origin restriction</a>
   319        <li><a href="#allowing-cross-origin-font-loading"><span
   320         class=secno>4.9.2 </span>Allowing cross-origin font loading</a>
   321       </ul>
   322     </ul>
   324    <li><a href="#font-matching-algorithm"><span class=secno>5 </span>Font
   325     Matching Algorithm</a>
   326     <ul class=toc>
   327      <li><a href="#font-family-casing"><span class=secno>5.1 </span>Case
   328       sensitivity of font family names</a>
   330      <li><a href="#font-style-matching"><span class=secno>5.2 </span>Matching
   331       font styles</a>
   333      <li><a href="#cluster-matching"><span class=secno>5.3 </span>Cluster
   334       matching</a>
   336      <li><a href="#char-handling-issues"><span class=secno>5.4
   337       </span>Character handling issues</a>
   339      <li><a href="#font-matching-changes"><span class=secno>5.5 </span>Font
   340       matching changes since CSS 2.1</a>
   342      <li><a href="#font-matching-examples"><span class=secno>5.6 </span>Font
   343       matching examples</a>
   344     </ul>
   346    <li><a href="#font-rend-props"><span class=secno>6 </span>Font Feature
   347     Properties</a>
   348     <ul class=toc>
   349      <li><a href="#glyph-selection-positioning"><span class=secno>6.1
   350       </span>Glyph selection and positioning</a>
   352      <li><a href="#language-specific-support"><span class=secno>6.2
   353       </span>Language-specific display</a>
   355      <li><a href="#font-kerning-prop"><span class=secno>6.3 </span>Kerning:
   356       the font-kerning property</a>
   358      <li><a href="#font-variant-ligatures-prop"><span class=secno>6.4
   359       </span>Ligatures: the font-variant-ligatures property</a>
   361      <li><a href="#font-variant-position-prop"><span class=secno>6.5
   362       </span>Subscript and superscript forms: the font-variant-position
   363       property</a>
   365      <li><a href="#font-variant-caps-prop"><span class=secno>6.6
   366       </span>Capitalization: the font-variant-caps property</a>
   368      <li><a href="#font-variant-numeric-prop"><span class=secno>6.7
   369       </span>Numerical formatting: the font-variant-numeric property</a>
   371      <li><a href="#font-variant-alternates-prop"><span class=secno>6.8
   372       </span>Alternates and swashes: the font-variant-alternates property</a>
   375      <li><a href="#font-feature-values"><span class=secno>6.9 </span>Defining
   376       font specific alternates: the <code>@font-feature-values</code>
   377       rule</a>
   378       <ul class=toc>
   379        <li><a href="#basic-syntax"><span class=secno>6.9.1 </span>Basic
   380         syntax</a>
   382        <li><a href="#multi-valued-feature-value-definitions"><span
   383         class=secno>6.9.2 </span>Multi-valued feature value definitions</a>
   384       </ul>
   386      <li><a href="#font-variant-east-asian-prop"><span class=secno>6.10
   387       </span>East Asian text rendering: the font-variant-east-asian
   388       property</a>
   390      <li><a href="#font-variant-prop"><span class=secno>6.11 </span>Overall
   391       shorthand for font rendering: the font-variant property</a>
   393      <li><a href="#font-feature-settings-prop"><span class=secno>6.12
   394       </span>Low-level font feature settings control: the
   395       font-feature-settings property</a>
   397      <li><a href="#font-language-override-prop"><span class=secno>6.13
   398       </span>Font language override: the font-language-override property</a>
   399     </ul>
   401    <li><a href="#font-feature-resolution"><span class=secno>7 </span>Font
   402     Feature Resolution </a>
   403     <ul class=toc>
   404      <li><a href="#default-features"><span class=secno>7.1 </span>Default
   405       features</a>
   407      <li><a href="#feature-precedence"><span class=secno>7.2 </span>Feature
   408       precedence</a>
   410      <li><a href="#feature-precedence-examples"><span class=secno>7.3
   411       </span>Feature precedence examples</a>
   412     </ul>
   414    <li><a href="#object-model"><span class=secno>8 </span>Object Model</a>
   415     <ul class=toc>
   416      <li><a href="#om-fontface"><span class=secno>8.1 </span>The
   417       <code>CSSFontFaceRule</code> interface</a>
   419      <li><a href="#om-fontfeaturevalues"><span class=secno>8.2 </span>The
   420       <code>CSSFontFeatureValuesRule</code> interface</a>
   421     </ul>
   423    <li class=no-num><a href="#platform-props-to-css">Appendix A: Mapping
   424     platform font properties to CSS properties</a>
   426    <li class=no-num><a href="#ch-ch-ch-changes">Changes</a>
   427     <ul class=toc>
   428      <li class=no-num><a href="#recent-changes"> Changes from the February
   429       2013 CSS3 Fonts Working Draft</a>
   430     </ul>
   432    <li class=no-num><a href="#acknowledgments">Acknowledgments</a>
   434    <li class=no-num><a href="#conformance"> Conformance</a>
   435     <ul class=toc>
   436      <li class=no-num><a href="#conventions"> Document Conventions</a>
   438      <li class=no-num><a href="#conformance-classes"> Conformance Classes</a>
   441      <li class=no-num><a href="#partial"> Partial Implementations</a>
   443      <li class=no-num><a href="#experimental"> Experimental
   444       Implementations</a>
   446      <li class=no-num><a href="#testing"> Non-Experimental
   447       Implementations</a>
   448     </ul>
   450    <li class=no-num><a href="#references">References</a>
   451     <ul class=toc>
   452      <li class=no-num><a href="#normative-references">Normative
   453       References</a>
   455      <li class=no-num><a href="#other-references">Other References</a>
   456     </ul>
   458    <li class=no-num><a href="#index">Index</a>
   460    <li class=no-num><a href="#property-index">Property index</a>
   461   </ul>
   462   <!--end-toc-->
   464   <h2 id=introduction><span class=secno>1 </span>Introduction</h2>
   466   <p>A font provides a resource containing the visual representation of
   467    characters. At the simplest level it contains information that maps
   468    character codes to shapes (called glyphs) that represent these characters.
   469    Fonts sharing a common design style are commonly grouped into font
   470    families classified by a set of standard font properties. Within a family,
   471    the shape displayed for a given character can vary by stroke weight, slant
   472    or relative width, among others. An individual font face is described by a
   473    unique combination of these properties. For a given range of text, CSS
   474    font properties are used to select a font family and a specific font face
   475    within that family to be used when rendering that text. As a simple
   476    example, to use the bold form of Helvetica one could use:
   478   <pre>body {
   479     font-family: Helvetica;
   480     font-weight: bold;
   481 }</pre>
   483   <p>Font resources may be installed locally on the system on which a user
   484    agent is running or downloadable. For local font resources descriptive
   485    information can be obtained directly from the font resource. For
   486    downloadable font resources (sometimes referred to as web fonts), the
   487    descriptive information is included with the reference to the font
   488    resource.
   490   <p>Families of fonts typically don't contain a single face for each
   491    possible variation of font properties. The CSS font selection mechanism
   492    describes how to match a given set of CSS font properties to a single font
   493    face.
   495   <h2 id=typography-background><span class=secno>2 </span>Typography
   496    Background</h2>
   498   <p><em>This section is non-normative.</em>
   500   <p> Typographic traditions vary across the globe, so there is no unique way
   501    to classify all fonts across languages and cultures. For even common Latin
   502    letters, wide variations are possible:
   504   <div class=figure><img alt="variations in glyphs for a single character"
   505    src=aaaaaa.png>
   506    <p class=caption>One character, many glyph variations
   507   </div>
   509   <p>Differences in the anatomy of letterforms is one way to distinguish
   510    fonts. For Latin fonts, flourishes at the ends of a character's main
   511    strokes, or serifs, can distinguish a font from those without. Similar
   512    comparisons exist in non-Latin fonts between fonts with tapered strokes
   513    and those using primarily uniform strokes:
   515   <div class=figure><img alt="serif vs. non-serifs" src=serifvssansserif.png>
   516    <p class=caption>Letterforms with and without serifs
   517   </div>
   519   <div class=figure><img alt="serif vs. non-serifs for japanese"
   520    src=minchovsgothic.png>
   521    <p class=caption>Similar groupings for Japanese typefaces
   522   </div>
   524   <p>Fonts contain letterforms and the data needed to map characters to these
   525    letterforms. Often this may be a simple one-to-one mapping, but more
   526    complex mappings are also possible. The use of combining diacritic marks
   527    creates many variations for an underlying letterform:
   529   <div class=figure><img alt="diacritic marks" src=aaaaaa-diacritics.png>
   530    <p class=caption>Variations with diacritic marks
   531   </div>
   533   <p>A sequence of characters can be represented by a single glyph known as a
   534    ligature:
   536   <div class=figure><img alt="example of a fi ligature"
   537    src=final-ligature.png>
   538    <p class=caption>Ligature example
   539   </div>
   541   <p>Visual transformations based on textual context are often stylistic
   542    option in European languages. They are required to correctly render
   543    languages like Arabic, the lam and alef characters below <em>must</em> be
   544    combined when they exist in sequence:
   546   <div class=figure><img alt="lam alef ligature" src=lamaleflig.png>
   547    <p class=caption>Required Arabic ligature
   548   </div>
   550   <p>The relative complexity of these shaping transformations requires
   551    additional data within the font.
   553   <p>Sets of font faces with various stylistic variations are often grouped
   554    together into font families. In the simplest case a regular face is
   555    supplemented with bold and italic faces, but much more extensive groupings
   556    are possible. Variations in the thickness of letterform strokes, the <dfn
   557    id=weight>weight</dfn>, and the overall proportions of the letterform, the
   558    <dfn id=width>width</dfn>, are most common. In the example below, each
   559    letter uses a different font face within the Univers font family. The
   560    width used increases from top to bottom and the weight increases from left
   561    to right:
   563   <div class=figure><img alt="various width and weight variations within a
   564    single family" src=weightwidthvariations.png>
   565    <p class=caption>Weight and width variations within a single font family
   566   </div>
   568   <p>Creating fonts that support multiple scripts is a difficult task;
   569    designers need to understand the cultural traditions surrounding the use
   570    of type in different scripts and come up with letterforms that somehow
   571    share a common theme. Many languages often share a common script and each
   572    of these languages may have noticeable stylistic differences. For example,
   573    the Arabic script is shared by Persian and Urdu and Cyrillic is used with
   574    many languages, not just Russian.
   576   <p>The <a href="#character-map"><em>character map</em></a> of a font
   577    defines the mapping of characters to glyphs for that font. If a document
   578    contains characters not supported by the <a href="#character-map"><em
   579    title="character map">character maps</em></a> of the fonts contained in a
   580    font family list, a user agent may use a <a
   581    href="#system-font-fallback"><em>system font fallback</em></a> procedure
   582    to locate an appropriate font that does. If no appropriate font can be
   583    found, some form of "missing glyph" character will be rendered by the user
   584    agent. System fallback can occur when the specified list of font families
   585    does not include a font that supports a given character.
   587   <p>Although the <a href="#character-map"><em>character map</em></a> of a
   588    font maps a given character to a glyph for that character, modern font
   589    technologies such as OpenType and AAT (Apple Advanced Typography) provide
   590    ways of mapping a character to different glyphs based upon feature
   591    settings. Fonts in these formats allow these features to be embedded in
   592    the font itself and controlled by applications. Common typographic
   593    features which can be specified this way include ligatures, swashes,
   594    contextual alternates, proportional and tabular figures, and automatic
   595    fractions, to list just a few. For a visual overview of OpenType features,
   596    see the <a href="#OPENTYPE-FONT-GUIDE"
   597    rel=biblioentry>[OPENTYPE-FONT-GUIDE]<!--{{OPENTYPE-FONT-GUIDE}}--></a>.
   599   <h2 id=basic-font-props><span class=secno>3 </span>Basic Font Properties</h2>
   601   <p>The particular font face used to render a character is determined by the
   602    font family and other font properties that apply to a given element. This
   603    structure allows settings to be varied independent of each other.</p>
   604   <!-- prop: font-family -->
   606   <h3 id=font-family-prop><span class=secno>3.1 </span>Font family: the <a
   607    href="#propdef-font-family">font-family</a> property</h3>
   609   <table class=propdef id=namefont-familyvalue-ltfamily-namegt-ltg>
   610    <tbody>
   611     <tr>
   612      <td>Name:
   614      <td><dfn id=propdef-font-family
   615       title="font-family!!property">font-family</dfn>
   617     <tr>
   618      <td>Value:
   620      <td>[ <a href="#family-name-value"><var>&lt;family-name&gt;</var></a> |
   621       <a href="#generic-family-value"><var>&lt;generic-family&gt;</var></a> ]
   622       #
   624     <tr>
   625      <td>Initial:
   627      <td>depends on user agent
   629     <tr>
   630      <td>Applies to:
   632      <td>all elements
   634     <tr>
   635      <td>Inherited:
   637      <td>yes
   639     <tr>
   640      <td>Percentages:
   642      <td>N/A
   644     <tr>
   645      <td>Media:
   647      <td>visual
   649     <tr>
   650      <td>Computed value:
   652      <td>as specified
   654     <tr>
   655      <td>Animatable:
   657      <td>no
   658   </table>
   660   <p>This property specifies a prioritized list of font family names or
   661    generic family names. A font family defines a set of faces that vary in
   662    weight, width or slope. CSS uses the combination of a family name with
   663    other style attributes to select an individual face. Using this selection
   664    mechanism, rather than selecting a face via the style name as is often
   665    done in design applications, allows some degree of regularity in textual
   666    display when fallback occurs.
   668   <p class=note>Designers should note that the CSS definition of font
   669    attributes used for selection are explicitly not intended to define a font
   670    taxonomy. A type designer's idea of a family may often extend to a set of
   671    faces that vary along axes other than just the standard axes of weight,
   672    width and slope. A family may extend to include both a set of serif faces
   673    and a set of sans-serif faces or vary along axes that are unique to that
   674    family. The CSS font selection mechanism merely provides a way to
   675    determine the “closest” substitute when substitution is necessary.
   677   <p>Unlike other CSS properties, component values are a comma-separated list
   678    indicating alternatives. A user agent iterates through the list of family
   679    names until it matches an available font that contains a glyph for the
   680    character to be rendered. This allows for differences in available fonts
   681    across platforms and for differences in the range of characters supported
   682    by individual fonts.
   684   <p>A font family name only specifies a name given to a set of font faces,
   685    it does not specify an individual face. For example, given the
   686    availability of the fonts below, Futura would match but Futura Medium
   687    would not:
   689   <div class=figure><img alt="family and face names"
   690    src=familyvsfacename.png>
   691    <p class=caption>Family and individual face names
   692   </div>
   694   <p>Consider the example below:
   696   <div class=example>
   697    <pre>body {
   698     font-family: Helvetica, Verdana, sans-serif;
   699 }</pre>
   701    <p>If Helvetica is available it will be used when rendering. If neither
   702     Helvetica nor Verdana is present, then the user-agent-defined sans serif
   703     font will be used.</p>
   704   </div>
   706   <p>There are two types of font family names:
   708   <dl>
   709    <dt><dfn id=family-name-value><var>&lt;family-name&gt;</var></dfn>
   711    <dd>The name of a font family of choice such as Helvetica or Verdana in
   712     the previous example.
   714    <dt><dfn id=generic-family-value><var>&lt;generic-family&gt;</var></dfn>
   716    <dd> The following generic family keywords are defined: ‘<a
   717     href="#serif"><code class=property>serif</code></a>’, ‘<a
   718     href="#sans-serif"><code class=property>sans-serif</code></a>’, ‘<a
   719     href="#cursive"><code class=property>cursive</code></a>’, ‘<a
   720     href="#fantasy"><code class=property>fantasy</code></a>’, and ‘<a
   721     href="#monospace"><code class=property>monospace</code></a>’. These
   722     keywords can be used as a general fallback mechanism when an author's
   723     desired font choices are not available. As keywords, they must not be
   724     quoted. Authors are encouraged to append a generic font family as a last
   725     alternative for improved robustness.
   726   </dl>
   728   <p>Font family names other than generic families must either be given
   729    quoted as <a
   730    href="//www.w3.org/TR/CSS21/syndata.html#strings">strings,</a> or unquoted
   731    as a sequence of one or more <a
   732    href="//www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers.</a>
   733    This means most punctuation characters and digits at the start of each
   734    token must be escaped in unquoted font family names.
   736   <p>To illustrate this, the following declarations are invalid:
   738   <pre>
   739 font-family: Red/Black, sans-serif;
   740 font-family: "Lucida" Grande, sans-serif;
   741 font-family: Ahem!, sans-serif;
   742 font-family: test@foo, sans-serif;
   743 font-family: #POUND, sans-serif;
   744 font-family: Hawaii 5-0, sans-serif;
   745 </pre>
   747   <p>If a sequence of identifiers is given as a font family name, the
   748    computed value is the name converted to a string by joining all the
   749    identifiers in the sequence by single spaces.
   751   <p>To avoid mistakes in escaping, it is recommended to quote font family
   752    names that contain white space, digits, or punctuation characters other
   753    than hyphens:
   755   <pre>
   756 body { font-family: "New Century Schoolbook", serif }
   758 &lt;BODY STYLE="font-family: '21st Century', fantasy">
   759 </pre>
   761   <p>Font family <em>names</em> that happen to be the same as a keyword value
   762    (‘<code class=property>inherit</code>’, ‘<a href="#serif"><code
   763    class=property>serif</code></a>’, ‘<a href="#sans-serif"><code
   764    class=property>sans-serif</code></a>’, ‘<a href="#monospace"><code
   765    class=property>monospace</code></a>’, ‘<a href="#fantasy"><code
   766    class=property>fantasy</code></a>’, and ‘<a href="#cursive"><code
   767    class=property>cursive</code></a>’) must be quoted to prevent confusion
   768    with the keywords with the same names. The keywords ‘<code
   769    class=property>initial</code>’ and ‘<code
   770    class=property>default</code>’ are reserved for future use and must also
   771    be quoted when used as font names. UAs must not consider these keywords as
   772    matching the <a
   773    href="#family-name-value"><var>&lt;family-name&gt;</var></a> type.
   775   <p>The precise way a set of fonts are grouped into font families varies
   776    depending upon the platform font management API's. The Windows GDI API
   777    only allows four faces to be grouped into a family while the DirectWrite
   778    API and API's on OSX and other platforms support font families with a
   779    variety of weights, widths and slopes (see <a
   780    href="#platform-props-to-css">Appendix A</a> for more details).
   782   <p>Some font formats allow fonts to carry multiple localizations of the
   783    family name. User agents must recognize and correctly match all of these
   784    names independent of the underlying platform localization, system API used
   785    or document encoding:
   787   <div class=figure><img alt="examples of localized family names"
   788    src=localizedfamilynames.png>
   789    <p class=caption>Localized family names
   790   </div>
   792   <h4 id=generic-font-families><span class=secno>3.1.1 </span>Generic font
   793    families</h4>
   795   <p>All five generic font families are defined to exist in all CSS
   796    implementations (they need not necessarily map to five distinct actual
   797    fonts). User agents should provide reasonable default choices for the
   798    generic font families, which express the characteristics of each family as
   799    well as possible within the limits allowed by the underlying technology.
   800    User agents are encouraged to allow users to select alternative choices
   801    for the generic fonts.
   803   <h5 class="no-num no-toc"> <span class=index-def id=serif0 title="serif,
   804    definition of"><a name=serif-def><dfn id=serif>serif</dfn></a></span></h5>
   806   <p>Serif fonts represent the formal text style for a script. This often
   807    means but is not limited to glyphs that have finishing strokes, flared or
   808    tapering ends, or have actual serifed endings (including slab serifs).
   809    Serif fonts are typically proportionately-spaced. They often display a
   810    greater variation between thick and thin strokes than fonts from the ‘<a
   811    href="#sans-serif"><code class=property>sans-serif</code></a>’ generic
   812    font family. CSS uses the term ‘<a href="#serif"><code
   813    class=property>serif</code></a>’ to apply to a font for any script,
   814    although other names may be more familiar for particular scripts, such as
   815    Mincho (Japanese), Sung, Song or Kai (Chinese), Batang (Korean). For
   816    Arabic, the Naskh style would correspond to ‘<a href="#serif"><code
   817    class=property>serif</code></a>’ more due to its typographic role rather
   818    than its actual design style. Any font that is so described may be used to
   819    represent the generic ‘<a href="#serif"><code
   820    class=property>serif</code></a>’ family.
   822   <div class=figure><img alt="sample serif fonts" src=serifexamples.png>
   823    <p class=caption>Sample serif fonts
   824   </div>
   826   <h5 class="no-num no-toc"> <span class=index-def id=sans-serif0
   827    title="sans-serif, definition of"> <a name=sans-serif-def><dfn
   828    id=sans-serif>sans-serif</dfn></a></span></h5>
   830   <p>Glyphs in sans-serif fonts, as the term is used in CSS, are generally
   831    low contrast (vertical and horizontal stems have the close to the same
   832    thickness) and have stroke endings that are plain -- without any flaring,
   833    cross stroke, or other ornamentation. Sans-serif fonts are typically
   834    proportionately-spaced. They often have little variation between thick and
   835    thin strokes, compared to fonts from the ‘<a href="#serif"><code
   836    class=property>serif</code></a>’ family. CSS uses the term ‘<a
   837    href="#sans-serif"><code class=property>sans-serif</code></a>’ to apply
   838    to a font for any script, although other names may be more familiar for
   839    particular scripts, such as Gothic (Japanese), Hei (Chinese), or Gulim
   840    (Korean). Any font that is so described may be used to represent the
   841    generic ‘<a href="#sans-serif"><code
   842    class=property>sans-serif</code></a>’ family.
   844   <div class=figure><img alt="sample sans-serif fonts"
   845    src=sansserifexamples.png>
   846    <p class=caption>Sample sans-serif fonts
   847   </div>
   849   <h5 class="no-num no-toc"> <span class=index-def id=cursive0
   850    title="cursive, definition of"> <a name=cursive-def><dfn
   851    id=cursive>cursive</dfn></a></span></h5>
   853   <p>Glyphs in cursive fonts generally use a more informal script style, and
   854    the result looks more like handwritten pen or brush writing than printed
   855    letterwork. CSS uses the term ‘<a href="#cursive"><code
   856    class=property>cursive</code></a>’ to apply to a font for any script,
   857    although other names such as Chancery, Brush, Swing and Script are also
   858    used in font names.
   860   <div class=figure><img alt="sample cursive fonts" src=cursiveexamples.png>
   861    <p class=caption>Sample cursive fonts
   862   </div>
   864   <h5 class="no-num no-toc"> <span class=index-def id=fantasy0
   865    title="fantasy, definition of"> <a name=fantasy-def><dfn
   866    id=fantasy>fantasy</dfn></a></span></h5>
   868   <p>Fantasy fonts are primarily decorative or expressive fonts that contain
   869    playful representations of characters. These do not include Pi or Picture
   870    fonts which do not represent actual characters.
   872   <div class=figure><img alt="sample fantasy fonts" src=fantasyexamples.png>
   873    <p class=caption>Sample fantasy fonts
   874   </div>
   876   <h5 class="no-num no-toc"> <span class=index-def id=monospace0
   877    title="monospace, definition of"> <a name=monospace-def><dfn
   878    id=monospace>monospace</dfn></a></span></h5>
   880   <p>The sole criterion of a monospace font is that all glyphs have the same
   881    fixed width. This is often used to render samples of computer code.
   883   <div class=figure><img alt="sample monospace fonts"
   884    src=monospaceexamples.png>
   885    <p class=caption>Sample monospace fonts
   886   </div>
   887   <!-- prop: font-weight -->
   889   <h3 id=font-weight-prop><span class=secno>3.2 </span>Font weight: the <a
   890    href="#propdef-font-weight">font-weight</a> property</h3>
   892   <table class=propdef id=namefont-weightvaluenormal-bold-bolder-l>
   893    <tbody>
   894     <tr>
   895      <td>Name:
   897      <td><dfn id=propdef-font-weight
   898       title="font-weight!!property">font-weight</dfn>
   900     <tr>
   901      <td>Value:
   903      <td><a href="#font-weight-normal-value"
   904       title="normal!!font-weight">normal</a> | <a href="#bold">bold</a> | <a
   905       href="#bolder">bolder</a> | <a href="#lighter">lighter</a> | <a
   906       href="#font-weight-numeric-values" title="100...900 weight
   907       values">100</a> | <a href="#font-weight-numeric-values"
   908       title="100...900 weight values">200</a> | <a
   909       href="#font-weight-numeric-values" title="100...900 weight
   910       values">300</a> | <a href="#font-weight-numeric-values"
   911       title="100...900 weight values">400</a> | <a
   912       href="#font-weight-numeric-values" title="100...900 weight
   913       values">500</a> | <a href="#font-weight-numeric-values"
   914       title="100...900 weight values">600</a> | <a
   915       href="#font-weight-numeric-values" title="100...900 weight
   916       values">700</a> | <a href="#font-weight-numeric-values"
   917       title="100...900 weight values">800</a> | <a
   918       href="#font-weight-numeric-values" title="100...900 weight
   919       values">900</a>
   921     <tr>
   922      <td>Initial:
   924      <td>normal
   926     <tr>
   927      <td>Applies to:
   929      <td>all elements
   931     <tr>
   932      <td>Inherited:
   934      <td>yes
   936     <tr>
   937      <td>Percentages:
   939      <td>N/A
   941     <tr>
   942      <td>Media:
   944      <td>visual
   946     <tr>
   947      <td>Computed value:
   949      <td>numeric weight value (see description)
   951     <tr>
   952      <td>Animatable:
   954      <td>as <a
   955       href="http://dev.w3.org/csswg/css3-transitions/#animtype-font-weight">font
   956       weight</a>
   957   </table>
   959   <p>The <a href="#propdef-font-weight"
   960    title="font-weight!!property">‘<code
   961    class=property>font-weight</code>’</a> property specifies the weight of
   962    glyphs in the font, their degree of blackness or stroke thickness.
   964   <p>Values have the following meanings:
   966   <dl>
   967    <dt><dfn id=font-weight-numeric-values title="100...900 weight values">100
   968     to 900</dfn>
   970    <dd>These values form an ordered sequence, where each number indicates a
   971     weight that is at least as dark as its predecessor. These roughly
   972     correspond to the commonly used weight names below:
   973   </dl>
   975   <ul>
   976    <li>100 - Thin
   978    <li>200 - Extra Light (Ultra Light)
   980    <li>300 - Light
   982    <li>400 - Normal
   984    <li>500 - Medium
   986    <li>600 - Semi Bold (Demi Bold)
   988    <li>700 - Bold
   990    <li>800 - Extra Bold (Ultra Bold)
   992    <li>900 - Black (Heavy)
   993   </ul>
   995   <dl>
   996    <dt><dfn id=font-weight-normal-value
   997     title="normal!!font-weight">normal</dfn>
   999    <dd>Same as ‘<code class=css>400</code>’.
  1001    <dt><dfn id=bold>bold</dfn>
  1003    <dd>Same as ‘<code class=css>700</code>’.
  1005    <dt><dfn id=bolder>bolder</dfn>
  1007    <dd>Specifies a bolder weight than the inherited value.
  1009    <dt><dfn id=lighter>lighter</dfn>
  1011    <dd>Specifies a lighter weight than the inherited value.
  1012   </dl>
  1014   <p>Font formats that use a scale other than a nine-step scale should map
  1015    their scale onto the CSS scale so that 400 roughly corresponds with a face
  1016    that would be labeled as Regular, Book, Roman and 700 roughly matches a
  1017    face that would be labeled as Bold. Or weights may be inferred from the
  1018    style names, ones that correspond roughly with the scale above. The scale
  1019    is relative, so a face with a larger weight value must never appear
  1020    lighter. If style names are used to infer weights, care should be taken to
  1021    handle variations in style names across locales.
  1023   <p>Quite often there are only a few weights available for a particular font
  1024    family. When a weight is specified for which no face exists, a face with a
  1025    nearby weight is used. In general, bold weights map to faces with heavier
  1026    weights and light weights map to faces with lighter weights (see the <a
  1027    href="#font-matching-algorithm">font matching section below</a> for a
  1028    precise definition). The examples here illustrate which face is used for
  1029    different weights, grey indicates a face for that weight does not exist so
  1030    a face with a nearby weight is used:
  1032   <div class=figure><img alt="weight mappings for a family with 400, 700 and
  1033    900 weights" src=optimaweights.png>
  1034    <p class=caption>Weight mappings for a font family with 400, 700 and 900
  1035     weight faces
  1036   </div>
  1038   <div class=figure><img alt="weight mappings for a family with 300, 600
  1039    weights" src=hiraginoweights.png>
  1040    <p class=caption>Weight mappings for a font family with 300 and 600 weight
  1041     faces
  1042   </div>
  1044   <p>Although the practice is not well-loved by typographers, bold faces are
  1045    often synthesized by user agents for faces that lack actual bold faces.
  1046    For the purposes of style matching, these faces must be treated as if they
  1047    exist within the family. Authors can explicitly avoid this behavior by
  1048    using the ‘<a href="#propdef-font-synthesis"><code
  1049    class=property>font-synthesis</code></a>’ property.
  1051   <p>Specified values of ‘<a href="#bolder"><code
  1052    class=property>bolder</code></a>’ and ‘<a href="#lighter"><code
  1053    class=property>lighter</code></a>’ indicate weights relative to the
  1054    weight of the parent element. The computed weight is calculated based on
  1055    the inherited <a href="#propdef-font-weight"
  1056    title="font-weight!!property">‘<code
  1057    class=property>font-weight</code>’</a> value using the chart below.
  1059   <table class=data id=bolderlighter summary="Bolder/lighter mappings">
  1060    <thead>
  1061     <tr>
  1062      <th>Inherited value
  1064      <th>bolder
  1066      <th>lighter
  1068    <tbody>
  1069     <tr>
  1070      <th>100
  1072      <td>400
  1074      <td>100
  1076     <tr>
  1077      <th>200
  1079      <td>400
  1081      <td>100
  1083     <tr>
  1084      <th>300
  1086      <td>400
  1088      <td>100
  1090     <tr>
  1091      <th>400
  1093      <td>700
  1095      <td>100
  1097     <tr>
  1098      <th>500
  1100      <td>700
  1102      <td>100
  1104     <tr>
  1105      <th>600
  1107      <td>900
  1109      <td>400
  1111     <tr>
  1112      <th>700
  1114      <td>900
  1116      <td>400
  1118     <tr>
  1119      <th>800
  1121      <td>900
  1123      <td>700
  1125     <tr>
  1126      <th>900
  1128      <td>900
  1130      <td>700
  1131   </table>
  1133   <p>The table above is equivalent to selecting the next relative bolder or
  1134    lighter face, given a font family containing normal and bold faces along
  1135    with a thin and a heavy face. Authors who desire finer control over the
  1136    exact weight values used for a given element may use numerical values
  1137    instead of relative weights.</p>
  1138   <!-- prop: font-stretch -->
  1140   <h3 id=font-stretch-prop><span class=secno>3.3 </span>Font width: the <a
  1141    href="#propdef-font-stretch">font-stretch</a> property</h3>
  1143   <table class=propdef id=namefont-stretchvalue-normal-ultra-conde>
  1144    <tbody>
  1145     <tr>
  1146      <td>Name:
  1148      <td><dfn id=propdef-font-stretch
  1149       title="font-stretch!!property">font-stretch</dfn>
  1151     <tr>
  1152      <td>Value:
  1154      <td> <a href="#font-stretch-normal-value"
  1155       title="normal!!font-stretch">normal</a> | <a
  1156       href="#ultra-condensed">ultra-condensed</a> | <a
  1157       href="#extra-condensed">extra-condensed</a> | <a
  1158       href="#condensed">condensed</a> | <a
  1159       href="#semi-condensed-">semi-condensed</a> | <a
  1160       href="#semi-expanded">semi-expanded</a> | <a
  1161       href="#expanded">expanded</a> | <a
  1162       href="#extra-expanded">extra-expanded</a> | <a
  1163       href="#ultra-expanded">ultra-expanded</a>
  1165     <tr>
  1166      <td>Initial:
  1168      <td>normal
  1170     <tr>
  1171      <td>Applies to:
  1173      <td>all elements
  1175     <tr>
  1176      <td>Inherited:
  1178      <td>yes
  1180     <tr>
  1181      <td>Percentages:
  1183      <td>N/A
  1185     <tr>
  1186      <td>Media:
  1188      <td>visual
  1190     <tr>
  1191      <td>Computed value:
  1193      <td>as specified
  1195     <tr>
  1196      <td>Animatable:
  1198      <td>as <a href="#font-stretch-animation">font stretch</a>
  1199   </table>
  1201   <p>The <a href="#propdef-font-stretch"
  1202    title="font-stretch!!property">‘<code
  1203    class=property>font-stretch</code>’</a> property selects a normal,
  1204    condensed, or expanded face from a font family. Absolute keyword values
  1205    have the following ordering, from narrowest to widest:
  1207   <ul>
  1208    <li><dfn id=ultra-condensed>ultra-condensed</dfn>
  1210    <li><dfn id=extra-condensed>extra-condensed</dfn>
  1212    <li><dfn id=condensed>condensed</dfn>
  1214    <li><dfn id=semi-condensed->semi-condensed </dfn>
  1216    <li><dfn id=font-stretch-normal-value
  1217     title="normal!!font-stretch">normal</dfn>
  1219    <li><dfn id=semi-expanded>semi-expanded</dfn>
  1221    <li><dfn id=expanded>expanded</dfn>
  1223    <li><dfn id=extra-expanded>extra-expanded</dfn>
  1225    <li><dfn id=ultra-expanded>ultra-expanded</dfn>
  1226   </ul>
  1228   <p>When a face does not exist for a given width, normal or condensed values
  1229    map to a narrower face, otherwise a wider face. Conversely, expanded
  1230    values map to a wider face, otherwise a narrower face. The figure below
  1231    shows how the nine font-stretch property settings affect font selection
  1232    for font family containing a variety of widths, grey indicates a width for
  1233    which no face exists and a different width is substituted:
  1235   <div class=figure><img alt="width mappings for a family with condensed,
  1236    normal and expanded faces" src=universwidths.png>
  1237    <p class=caption>Width mappings for a font family with condensed, normal
  1238     and expanded width faces
  1239   </div>
  1241   <p id=font-stretch-animation>Animation of font stretch: Font stretch is
  1242    interpolated in discrete steps. The interpolation happens as though the
  1243    ordered values are equally spaced real numbers. The interpolation result
  1244    is rounded to the nearest value, with values exactly halfway between two
  1245    values rounded towards the later value in the list above.</p>
  1246   <!-- prop: font-style -->
  1248   <h3 id=font-style-prop><span class=secno>3.4 </span>Font style: the <a
  1249    href="#propdef-font-style">font-style</a> property</h3>
  1251   <table class=propdef id=namefont-stylevaluenormal-italic-oblique>
  1252    <tbody>
  1253     <tr>
  1254      <td>Name:
  1256      <td><dfn id=propdef-font-style
  1257       title="font-style!!property">font-style</dfn>
  1259     <tr>
  1260      <td>Value:
  1262      <td><a href="#font-style-normal-value"
  1263       title="normal!!font-style">normal</a> | <a href="#italic">italic</a> |
  1264       <a href="#oblique">oblique</a>
  1266     <tr>
  1267      <td>Initial:
  1269      <td>normal
  1271     <tr>
  1272      <td>Applies to:
  1274      <td>all elements
  1276     <tr>
  1277      <td>Inherited:
  1279      <td>yes
  1281     <tr>
  1282      <td>Percentages:
  1284      <td>N/A
  1286     <tr>
  1287      <td>Media:
  1289      <td>visual
  1291     <tr>
  1292      <td>Computed value:
  1294      <td>as specified
  1296     <tr>
  1297      <td>Animatable:
  1299      <td>no
  1300   </table>
  1302   <p>The <a href="#propdef-font-style" title="font-style!!property">‘<code
  1303    class=property>font-style</code>’</a> property allows italic or oblique
  1304    faces to be selected. Italic forms are generally cursive in nature while
  1305    oblique faces are typically sloped versions of the regular face. Oblique
  1306    faces can be simulated by artificially sloping the glyphs of the regular
  1307    face. Compare the artificially sloped renderings of Palatino ‘<code
  1308    class=property>a</code>’ and Baskerville ‘<code
  1309    class=property>N</code>’ in grey with the actual italic versions:
  1311   <div class=figure><img alt="artificial sloping vs. real italics"
  1312    src=realvsfakeitalics.png>
  1313    <p class=caption>Artificial sloping versus real italics
  1314   </div>
  1316   <p>Values have the following meanings:
  1318   <dl>
  1319    <dt><dfn id=font-style-normal-value
  1320     title="normal!!font-style">normal</dfn>
  1322    <dd>selects a face that is classified as a normal face, one that is
  1323     neither italic or obliqued
  1325    <dt><dfn id=italic>italic</dfn>
  1327    <dd>selects a font that is labeled as an italic face, or an oblique face
  1328     if one is not
  1330    <dt><dfn id=oblique>oblique</dfn>
  1332    <dd>selects a font that is labeled as an oblique face, or an italic face
  1333     if one is not
  1334   </dl>
  1336   <p>If no italic or oblique face is available, oblique faces can be
  1337    synthesized by rendering non-obliqued faces with an artificial obliquing
  1338    operation. The use of these artificially obliqued faces can be disabled
  1339    using the ‘<a href="#propdef-font-synthesis"><code
  1340    class=property>font-synthesis</code></a>’ property. The details of the
  1341    obliquing operation are not explicitly defined.</p>
  1342   <!-- resolution on the "undefined" nature of synthetics: http://www.w3.org/2013/06/06-css-minutes.html#item03 -->
  1344   <p>Many scripts lack the tradition of mixing a cursive form within text
  1345    rendered with a normal face. Chinese, Japanese and Korean fonts almost
  1346    always lack italic or oblique faces. Fonts that support a mixture of
  1347    scripts will sometimes omit specific scripts such as Arabic from the set
  1348    of glyphs supported in the italic face. User agents should be careful
  1349    about making <a href="#character-map"><em>character map</em></a>
  1350    assumptions across faces when implementing support for <a
  1351    href="#system-font-fallback"><em>system font fallback</em></a>.</p>
  1352   <!-- prop: font-size -->
  1354   <h3 id=font-size-prop><span class=secno>3.5 </span>Font size: the <a
  1355    href="#propdef-font-size">font-size</a> property</h3>
  1357   <table class=propdef id=namefont-sizevalueltabsolute-sizegt-ltre>
  1358    <tbody>
  1359     <tr>
  1360      <td>Name:
  1362      <td><dfn id=propdef-font-size>font-size</dfn>
  1364     <tr>
  1365      <td>Value:
  1367      <td><a href="#absolute-size-value"><var>&lt;absolute-size&gt;</var></a>
  1368       | <a href="#relative-size-value"><var>&lt;relative-size&gt;</var></a> |
  1369       <a href="#length-size-value"><var>&lt;length&gt;</var></a> | <a
  1370       href="#percentage-size-value"><var>&lt;percentage&gt;</var></a>
  1372     <tr>
  1373      <td>Initial:
  1375      <td>medium
  1377     <tr>
  1378      <td>Applies to:
  1380      <td>all elements
  1382     <tr>
  1383      <td>Inherited:
  1385      <td>yes
  1387     <tr>
  1388      <td>Percentages:
  1390      <td>refer to parent element's font size
  1392     <tr>
  1393      <td>Media:
  1395      <td>visual
  1397     <tr>
  1398      <td>Computed value:
  1400      <td>absolute length
  1402     <tr>
  1403      <td>Animatable:
  1405      <td>as <a
  1406       href="http://dev.w3.org/csswg/css3-transitions/#animtype-length">length</a>
  1407   </table>
  1409   <p>This property indicates the desired height of glyphs from the font. For
  1410    scalable fonts, the font-size is a scale factor applied to the EM unit of
  1411    the font. (Note that certain glyphs may bleed outside their EM box.) For
  1412    non-scalable fonts, the font-size is converted into absolute units and
  1413    matched against the declared font-size of the font, using the same
  1414    absolute coordinate space for both of the matched values. Values have the
  1415    following meanings:
  1417   <dl>
  1418    <dt><dfn id=absolute-size-value><var>&lt;absolute-size&gt;</var></dfn>
  1420    <dd> An <a
  1421     href="#absolute-size-value"><var>&lt;absolute-size&gt;</var></a> keyword
  1422     refers to an entry in a table of font sizes computed and kept by the user
  1423     agent. Possible values are:
  1424     <p> [ xx-small | x-small | small | medium | large | x-large | xx-large ]</p>
  1426    <dt><dfn id=relative-size-value><var>&lt;relative-size&gt;</var></dfn>
  1428    <dd> A <a href="#relative-size-value"><var>&lt;relative-size&gt;</var></a>
  1429     keyword is interpreted relative to the table of font sizes and the
  1430     computed ‘<a href="#propdef-font-size"><code
  1431     class=property>font-size</code></a>’ of the parent element. Possible
  1432     values are:
  1433     <p> [ larger | smaller ]
  1435     <p> For example, if the parent element has a font size of ‘<code
  1436      class=property>medium</code>’, a value of ‘<code
  1437      class=property>larger</code>’ will make the font size of the current
  1438      element be ‘<code class=property>large</code>’. If the parent
  1439      element's size is not close to a table entry, the user agent is free to
  1440      interpolate between table entries or round off to the closest one. The
  1441      user agent may have to extrapolate table values if the numerical value
  1442      goes beyond the keywords.
  1444    <dt><dfn id=length-size-value><var>&lt;length&gt;</var></dfn>
  1446    <dd>A length value specifies an absolute font size (independent of the
  1447     user agent's font table). Negative lengths are illegal.
  1449    <dt><dfn id=percentage-size-value><var>&lt;percentage&gt;</var></dfn>
  1451    <dd>A percentage value specifies an absolute font size relative to the
  1452     parent element's font size. Use of percentage values, or values in
  1453     ‘<code class=property>em</code>’s, leads to more robust and
  1454     cascadable style sheets.
  1455   </dl>
  1457   <p>The following table provides user agent guidelines for the absolute-size
  1458    scaling factor and their mapping to HTML heading and absolute font-sizes.
  1459    The ‘<code class=property>medium</code>’ value is used as the
  1460    reference middle value. The user agent may fine-tune these values for
  1461    different fonts or different types of display devices.
  1463   <table class=data>
  1464    <thead>
  1465     <tr>
  1466      <th>CSS absolute-size values
  1468      <th>xx-small
  1470      <th>x-small
  1472      <th>small
  1474      <th>medium
  1476      <th>large
  1478      <th>x-large
  1480      <th>xx-large
  1482      <th> 
  1484    <tbody>
  1485     <tr>
  1486      <th>scaling factor
  1488      <td>3/5
  1490      <td>3/4
  1492      <td>8/9
  1494      <td>1
  1496      <td>6/5
  1498      <td>3/2
  1500      <td>2/1
  1502      <td>3/1
  1504     <tr>
  1505      <th>HTML headings
  1507      <td>h6
  1509      <td> 
  1511      <td>h5
  1513      <td>h4
  1515      <td>h3
  1517      <td>h2
  1519      <td>h1
  1521      <td> 
  1523     <tr>
  1524      <th>HTML font sizes
  1526      <td>1
  1528      <td> 
  1530      <td>2
  1532      <td>3
  1534      <td>4
  1536      <td>5
  1538      <td>6
  1540      <td>7
  1541   </table>
  1543   <p class=note><em><strong>Note 1.</strong> To preserve readability, an UA
  1544    applying these guidelines should nevertheless avoid creating font-size
  1545    resulting in less than 9 device pixels per EM unit on a computer
  1546    display.</em>
  1548   <p class=note><em><strong>Note 2.</strong> In CSS1, the suggested scaling
  1549    factor between adjacent indexes was 1.5 which user experience proved to be
  1550    too large. In CSS2, the suggested scaling factor for computer screen
  1551    between adjacent indexes was 1.2 which still created issues for the small
  1552    sizes. The new scaling factor varies between each index to provide a
  1553    better readability.</em>
  1555   <p>The actual value of this property may differ from the computed value due
  1556    a numerical value on ‘<a href="#propdef-font-size-adjust"><code
  1557    class=property>font-size-adjust</code></a>’ and the unavailability of
  1558    certain font sizes.
  1560   <p>Child elements inherit the computed <a class=noxref
  1561    href="#font-size-prop"> <span class=property>‘<code
  1562    class=property>font-size</code>’</span></a> value (otherwise, the effect
  1563    of <a class=noxref href="#font-size-adjust-prop"><span
  1564    class=property>‘<code
  1565    class=property>font-size-adjust</code>’</span></a> would compound).
  1567   <div class=example>
  1568    <p style="display:none">Example(s):
  1570    <p>
  1572    <pre>p { font-size: 12pt; }
  1573 blockquote { font-size: larger }
  1574 em { font-size: 150% }
  1575 em { font-size: 1.5em }
  1576 </pre>
  1577   </div>
  1578   <!-- prop: font-size-adjust -->
  1580   <h3 id=font-size-adjust-prop><span class=secno>3.6 </span>Relative sizing:
  1581    the <a href="#propdef-font-size-adjust">font-size-adjust</a> property</h3>
  1583   <table class=propdef id=namefont-size-adjustvaluenone-auto-ltnum>
  1584    <tbody>
  1585     <tr>
  1586      <td>Name:
  1588      <td><dfn id=propdef-font-size-adjust>font-size-adjust</dfn>
  1590     <tr>
  1591      <td>Value:
  1593      <td><a href="#font-size-adjust-none-value"
  1594       title="none!!font-size-adjust">none</a> | <a
  1595       href="#font-size-adjust-auto-value"
  1596       title="auto!!font-size-adjust">auto</a> | <a
  1597       href="#aspect-ratio-value"><var>&lt;number&gt;</var></a>
  1599     <tr>
  1600      <td>Initial:
  1602      <td>none
  1604     <tr>
  1605      <td>Applies to:
  1607      <td>all elements
  1609     <tr>
  1610      <td>Inherited:
  1612      <td>yes
  1614     <tr>
  1615      <td>Percentages:
  1617      <td>N/A
  1619     <tr>
  1620      <td>Media:
  1622      <td>visual
  1624     <tr>
  1625      <td>Computed value:
  1627      <td>as specified
  1629     <tr>
  1630      <td>Animatable:
  1632      <td>as <a
  1633       href="http://dev.w3.org/csswg/css3-transitions/#animtype-number">number</a>
  1634   </table>
  1636   <p>For any given font size, the apparent size and legibility of text varies
  1637    across fonts. For scripts such as Latin or Cyrillic that distinguish
  1638    between upper and lowercase letters, the relative height of lowercase
  1639    letters compared to their uppercase counterparts is a determining factor
  1640    of legibility. This is commonly referred to as the <a class=index-def
  1641    href="#aspect-value" id=aspect-value0 title="aspect value"><dfn
  1642    id=aspect-value>aspect value</dfn></a>. Precisely defined, it is equal to
  1643    the x-height of a font divided by the font size.
  1645   <p>In situations where font fallback occurs, fallback fonts may not share
  1646    the same aspect ratio as the desired font family and will thus appear less
  1647    readable. The font-size-adjust property is a way to preserve the
  1648    readability of text when font fallback occurs. It does this by adjusting
  1649    the font-size so that the x-height is the same regardless of the font
  1650    used.
  1652   <div class=example>
  1653    <p>The style defined below defines Verdana as the desired font family, but
  1654     if Verdana is not available Futura or Times will be used.</p>
  1656    <pre>p {
  1657     font-family: Verdana, Futura, Times;
  1660 &lt;p>Lorem ipsum dolor sit amet, ...&lt;/p>
  1661 </pre>
  1663    <p>Verdana has a relatively high aspect ratio, lowercase letters are
  1664     relatively tall compared to uppercase letters, so at small sizes text
  1665     appears legible. Times has a lower aspect ratio and so if fallback
  1666     occurs, the text will be less legible at small sizes than Verdana.</p>
  1667   </div>
  1669   <p>How text rendered in each of these fonts compares is shown below, the
  1670    columns show text rendered in Verdana, Futura and Times. The same
  1671    font-size value is used across cells within each row and red lines are
  1672    included to show the differences in x-height. In the upper half each row
  1673    is rendered in the same font-size value. The same is true for the lower
  1674    half but in this half the font-size-adjust property is also set so that
  1675    the actual font size is adjusted to preserve the x-height across each row.
  1676    Note how small text remains relatively legible across each row in the
  1677    lower half.
  1679   <div class=figure><img alt="text with and without font-size-adjust"
  1680    src=fontsizeadjust.png>
  1681    <p class=caption>Text with and without the use of font-size-adjust
  1682   </div>
  1684   <p>This property allows authors to specify an aspect value for an element
  1685    that will effectively preserve the x-height of the first choice font,
  1686    whether it is substituted or not. Values have the following meanings:
  1688   <dl>
  1689    <dt><dfn id=font-size-adjust-none-value
  1690     title="none!!font-size-adjust">none</dfn>
  1692    <dd>Do not preserve the font's x-height.
  1694    <dt><dfn id=font-size-adjust-auto-value
  1695     title="auto!!font-size-adjust">auto</dfn>
  1697    <dd>Behaves just like &lt;number>, except the number used is the aspect
  1698     value calculated by user agents for the first font in the list of fonts
  1699     defined for the initial value of the <a href="#propdef-font-family"
  1700     title="font-family!!property">‘<code
  1701     class=property>font-family</code>’</a> property. Effectively this is
  1702     the default font used when <a href="#propdef-font-family"
  1703     title="font-family!!property">‘<code
  1704     class=property>font-family</code>’</a> is not otherwise specified.
  1705     <p>Authors can use this value to specify that font size should be
  1706      normalized across fonts based on the x-height without the need to
  1707      specify the aspect ratio explicitly.</p>
  1709    <dt><dfn id=aspect-ratio-value><var>&lt;number&gt;</var></dfn>
  1711    <dd>Specifies the aspect value used in the calculation below to calculate
  1712     the adjusted font size:
  1713     <pre>c  =  ( a / a' ) s
  1714 </pre>
  1716     <p>where:</p>
  1718     <pre>s  =  font-size value
  1719 a  =  aspect value as specified by the font-size-adjust property
  1720 a' =  aspect value of actual font
  1721 c  =  adjusted font-size to use
  1722 </pre>
  1724     <p>This value applies to any font that is selected but in typical usage
  1725      it should be based on the aspect value of the first font in the
  1726      font-family list. If this is specified accurately, the <tt>(a/a')</tt>
  1727      term in the formula above is effectively 1 for the first font and no
  1728      adjustment occurs. If the value is specified inaccurately, text rendered
  1729      using the first font in the family list will display differently in
  1730      older user agents that don't support font-size-adjust.</p>
  1731   </dl>
  1733   <p>Authors can calculate the aspect value for a given font by comparing
  1734    spans with the same content but different font-size-adjust properties. If
  1735    the same font-size is used, the spans will match when the font-size-adjust
  1736    value is accurate for the given font.
  1738   <div class=example>
  1739    <p>Two spans with borders are used to determine the aspect value of a
  1740     font. The font-size is the same for both spans but the font-size-adjust
  1741     property is specified only for the right span. Starting with a value of
  1742     0.5, the aspect value can be adjusted until the borders around the two
  1743     letters line up.</p>
  1745    <pre>p {
  1746     font-family: Futura;
  1747     font-size: 500px;
  1750 span {
  1751     border: solid 1px red;
  1754 .adjust {
  1755     font-size-adjust: 0.5;
  1758 &lt;p>&lt;span>b&lt;/span>&lt;span class="adjust">b&lt;/span>&lt;/p>
  1759 </pre>
  1761    <div class=figure><img alt="Futura with an aspect value of 0.5"
  1762     src=beforefontsizeadjust.png>
  1763     <p class=caption>Futura with an aspect value of 0.5
  1764    </div>
  1766    <p>The box on the right is a bit bigger than the one on the left, so the
  1767     aspect value of this font is something less than 0.5. Adjust the value
  1768     until the boxes align.</p>
  1769   </div>
  1770   <!-- prop: font -->
  1772   <h3 id=font-prop><span class=secno>3.7 </span>Shorthand font property: the
  1773    <a href="#propdef-font">font</a> property</h3>
  1775   <table class=propdef id=namefontvalue-ltlsquofont-stylersquogt-l>
  1776    <tbody>
  1777     <tr>
  1778      <td>Name:
  1780      <td><dfn id=propdef-font>font</dfn>
  1782     <tr>
  1783      <td>Value:
  1785      <td>[ [ <var>&lt;<a href="#propdef-font-style"
  1786       title="font-style!!property">‘<code
  1787       class=property>font-style</code>’</a>&gt;</var> || <a
  1788       href="#font-variant-css21-values"><var>&lt;font-variant-css21&gt;</var></a>
  1789       || <var>&lt;<a href="#propdef-font-weight"
  1790       title="font-weight!!property">‘<code
  1791       class=property>font-weight</code>’</a>&gt;</var> || <var>&lt;<a
  1792       href="#propdef-font-stretch" title="font-stretch!!property">‘<code
  1793       class=property>font-stretch</code>’</a></var> ]? <var>&lt;‘<a
  1794       href="#propdef-font-size"><code
  1795       class=property>font-size</code></a>’&gt;</var> [ / <var>&lt;‘<code
  1796       class=property>line-height</code>’&gt;</var> ]? <var>&lt;<a
  1797       href="#propdef-font-family" title="font-family!!property">‘<code
  1798       class=property>font-family</code>’</a>&gt;</var> ] | caption | icon |
  1799       menu | message-box | small-caption | status-bar
  1801     <tr>
  1802      <td>Initial:
  1804      <td>see individual properties
  1806     <tr>
  1807      <td>Applies to:
  1809      <td>all elements
  1811     <tr>
  1812      <td>Inherited:
  1814      <td>yes
  1816     <tr>
  1817      <td>Percentages:
  1819      <td>see individual properties
  1821     <tr>
  1822      <td>Media:
  1824      <td>visual
  1826     <tr>
  1827      <td>Computed value:
  1829      <td>see individual properties
  1831     <tr>
  1832      <td>Animatable:
  1834      <td>see individual properties
  1835   </table>
  1837   <p>The <span class=property>‘<a href="#propdef-font"><code
  1838    class=property>font</code></a>’</span> property is, except as described
  1839    below, a shorthand property for setting <a href="#propdef-font-style"
  1840    title="font-style!!property">‘<code
  1841    class=property>font-style</code>’</a>, <a href="#propdef-font-variant"
  1842    title="font-variant!!property">‘<code
  1843    class=property>font-variant</code>’</a>, <a href="#propdef-font-weight"
  1844    title="font-weight!!property">‘<code
  1845    class=property>font-weight</code>’</a>, <a href="#propdef-font-stretch"
  1846    title="font-stretch!!property">‘<code
  1847    class=property>font-stretch</code>’</a>, <span class=property>‘<a
  1848    href="#propdef-font-size"><code
  1849    class=property>font-size</code></a>’</span>, <a class=property
  1850    href="http://www.w3.org/TR/CSS2/visudet.html#propdef-line-height">‘<code
  1851    class=property>line-height</code>’</a>, <a href="#propdef-font-family"
  1852    title="font-family!!property">‘<code
  1853    class=property>font-family</code>’</a> at the same place in the
  1854    stylesheet. Values for the <a href="#propdef-font-variant"
  1855    title="font-variant!!property">‘<code
  1856    class=property>font-variant</code>’</a> property may also be included
  1857    but only those supported in CSS 2.1, none of the <a
  1858    href="#propdef-font-variant" title="font-variant!!property">‘<code
  1859    class=property>font-variant</code>’</a> values added in this
  1860    specification can be used in the <span class=property>‘<a
  1861    href="#propdef-font"><code class=property>font</code></a>’</span>
  1862    shorthand:
  1864   <pre
  1865    class=prod><dfn id=font-variant-css21-values><var>&lt;font-variant-css21&gt;</var></dfn> = [normal | small-caps]</pre>
  1867   <p>The syntax of this property is based on a traditional typographical
  1868    shorthand notation to set multiple properties related to fonts.
  1870   <p>All subproperties of the ‘<a href="#propdef-font"><code
  1871    class=property>font</code></a>’ property are first reset to their
  1872    initial values, including those listed above plus <span
  1873    class=property>‘<a href="#propdef-font-size-adjust"><code
  1874    class=property>font-size-adjust</code></a>’</span>, <span
  1875    class=property>‘<a href="#propdef-font-kerning"><code
  1876    class=property>font-kerning</code></a>’</span>, subproperties of <a
  1877    href="#propdef-font-variant" title="font-variant!!property">‘<code
  1878    class=property>font-variant</code>’</a> and and <span>‘<a
  1879    href="#propdef-font-language-override"><code
  1880    class=property>font-language-override</code></a>’</span>. Then, those
  1881    properties that are given explicit values in the <span
  1882    class=property>‘<a href="#propdef-font"><code
  1883    class=property>font</code></a>’</span> shorthand are set to those
  1884    values. For a definition of allowed and initial values, see the previously
  1885    defined properties. For reasons of backwards compatibility, it is not
  1886    possible to set <span class=property>‘<a
  1887    href="#propdef-font-size-adjust"><code
  1888    class=property>font-size-adjust</code></a>’</span> to anything other
  1889    than its initial value using the <span class=property>‘<a
  1890    href="#propdef-font"><code class=property>font</code></a>’</span>
  1891    shorthand property; instead, use the individual property.
  1893   <div class=example>
  1894    <p style="display:none">Example(s):
  1896    <p>
  1898    <pre>p { font: 12pt/14pt sans-serif }
  1899 p { font: 80% sans-serif }
  1900 p { font: x-large/110% &quot;new century schoolbook&quot;, serif }
  1901 p { font: bold italic large Palatino, serif }
  1902 p { font: normal small-caps 120%/120% fantasy }
  1903 p { font: condensed oblique 12pt &quot;Helvetica Neue&quot;, serif; }
  1904 </pre>
  1906    <p> In the second rule, the font size percentage value (‘<code
  1907     class=css>80%</code>’) refers to the computed ‘<a
  1908     href="#propdef-font-size"><code class=property>font-size</code></a>’ of
  1909     the parent element. In the third rule, the line height percentage
  1910     (‘<code class=css>110%</code>’) refers to the font size of the
  1911     element itself.
  1913    <p>The first three rules do not specify the <a
  1914     href="#propdef-font-variant" title="font-variant!!property">‘<code
  1915     class=property>font-variant</code>’</a> and <a
  1916     href="#propdef-font-weight" title="font-weight!!property">‘<code
  1917     class=property>font-weight</code>’</a> explicitly, so these properties
  1918     receive their initial values (<span title="normal value">‘<code
  1919     class=property>normal</code>’</span>). Notice that the font family name
  1920     "new century schoolbook", which contains spaces, is enclosed in quotes.
  1921     The fourth rule sets the <a href="#propdef-font-weight"
  1922     title="font-weight!!property">‘<code
  1923     class=property>font-weight</code>’</a> to ‘<a href="#bold"><code
  1924     class=property>bold</code></a>’, the <a href="#propdef-font-style"
  1925     title="font-style!!property">‘<code
  1926     class=property>font-style</code>’</a> to ‘<a href="#italic"><code
  1927     class=property>italic</code></a>’, and implicitly sets <a
  1928     href="#propdef-font-variant" title="font-variant!!property">‘<code
  1929     class=property>font-variant</code>’</a> to <a
  1930     href="#font-variant-normal-value" title="normal!!font-variant">‘<code
  1931     class=property>normal</code>’</a>.
  1933    <p> The fifth rule sets the <a href="#propdef-font-variant"
  1934     title="font-variant!!property">‘<code
  1935     class=property>font-variant</code>’</a> (‘<a href="#small-caps"><code
  1936     class=property>small-caps</code></a>’), the <span class=property>‘<a
  1937     href="#propdef-font-size"><code
  1938     class=property>font-size</code></a>’</span> (120% of the parent's font
  1939     size), the <a class=property
  1940     href="http://www.w3.org/TR/CSS2/visudet.html#propdef-line-height">‘<code
  1941     class=property>line-height</code>’</a> (120% of the font size) and the
  1942     <a href="#propdef-font-family" title="font-family!!property">‘<code
  1943     class=property>font-family</code>’</a> (‘<a href="#fantasy"><code
  1944     class=property>fantasy</code></a>’). It follows that the keyword <span
  1945     title="normal value">‘<code class=property>normal</code>’</span>
  1946     applies to the two remaining properties: <a href="#propdef-font-style"
  1947     title="font-style!!property">‘<code
  1948     class=property>font-style</code>’</a> and <a
  1949     href="#propdef-font-weight" title="font-weight!!property">‘<code
  1950     class=property>font-weight</code>’</a>.
  1952    <p>The sixth rule sets the <a href="#propdef-font-style"
  1953     title="font-style!!property">‘<code
  1954     class=property>font-style</code>’</a>, <a href="#propdef-font-stretch"
  1955     title="font-stretch!!property">‘<code
  1956     class=property>font-stretch</code>’</a>, <span class=property>‘<a
  1957     href="#propdef-font-size"><code
  1958     class=property>font-size</code></a>’</span>, and <a
  1959     href="#propdef-font-family" title="font-family!!property">‘<code
  1960     class=property>font-family</code>’</a>, the other font properties being
  1961     set to their initial values.
  1962   </div>
  1964   <p>Since the <a href="#propdef-font-stretch"
  1965    title="font-stretch!!property">‘<code
  1966    class=property>font-stretch</code>’</a> property was not defined in CSS
  1967    2.1, when using <a href="#propdef-font-stretch"
  1968    title="font-stretch!!property">‘<code
  1969    class=property>font-stretch</code>’</a> values within ‘<a
  1970    href="#propdef-font"><code class=property>font</code></a>’ rules,
  1971    authors should include a extra version compatible with older user agents:
  1973   <pre>p {
  1974   font: 80% sans-serif;   /* for older user agents */
  1975   font: condensed 80% sans-serif;
  1976 }</pre>
  1978   <p>The following values refer to system fonts:
  1980   <dl>
  1981    <dt><strong>caption</strong>
  1983    <dd>The font used for captioned controls (e.g., buttons, drop-downs,
  1984     etc.).
  1986    <dt><strong>icon</strong>
  1988    <dd>The font used to label icons.
  1990    <dt><strong>menu</strong>
  1992    <dd>The font used in menus (e.g., dropdown menus and menu lists).
  1994    <dt><strong>message-box</strong>
  1996    <dd>The font used in dialog boxes.
  1998    <dt><strong>small-caption</strong>
  2000    <dd>The font used for labeling small controls.
  2002    <dt><strong>status-bar</strong>
  2004    <dd>The font used in window status bars.
  2005   </dl>
  2007   <p>System fonts may only be set as a whole; that is, the font family, size,
  2008    weight, style, etc. are all set at the same time. These values may then be
  2009    altered individually if desired. If no font with the indicated
  2010    characteristics exists on a given platform, the user agent should either
  2011    intelligently substitute (e.g., a smaller version of the ‘<code
  2012    class=property>caption</code>’ font might be used for the ‘<code
  2013    class=property>small-caption</code>’ font), or substitute a user agent
  2014    default font. As for regular fonts, if, for a system font, any of the
  2015    individual properties are not part of the operating system's available
  2016    user preferences, those properties should be set to their initial values.
  2018   <p>That is why this property is "almost" a shorthand property: system fonts
  2019    can only be specified with this property, not with <a
  2020    href="#propdef-font-family" title="font-family!!property">‘<code
  2021    class=property>font-family</code>’</a> itself, so <span
  2022    class=property>‘<a href="#propdef-font"><code
  2023    class=property>font</code></a>’</span> allows authors to do more than
  2024    the sum of its subproperties. However, the individual properties such as
  2025    <a href="#propdef-font-weight" title="font-weight!!property">‘<code
  2026    class=property>font-weight</code>’</a> are still given values taken from
  2027    the system font, which can be independently varied.
  2029   <p>Note that the keywords used for the system fonts listed above are only
  2030    treated as keywords when they occur in the initial position, in other
  2031    positions the same string is treated as part of the font family name:
  2033   <pre>  font: menu;        /* use the font settings for system menus */
  2034   font: large menu;  /* use a font family named "menu" */</pre>
  2036   <div class=example>
  2037    <p style="display:none">Example(s):
  2039    <p>
  2041    <pre>button { font: 300 italic 1.3em/1.7em &quot;FB Armada&quot;, sans-serif }
  2042 button p { font: menu }
  2043 button p em { font-weight: bolder }
  2044 </pre>
  2046    <p>If the font used for dropdown menus on a particular system happened to
  2047     be, for example, 9-point Charcoal, with a weight of 600, then P elements
  2048     that were descendants of BUTTON would be displayed as if this rule were
  2049     in effect:
  2051    <pre>button p { font: 600 9pt Charcoal }
  2052 </pre>
  2054    <p>Because the <span class=property>‘<a href="#propdef-font"><code
  2055     class=property>font</code></a>’</span> shorthand resets to its initial
  2056     value any property not explicitly given a value, this has the same effect
  2057     as this declaration:
  2059    <pre>button p {
  2060   font-style: normal;
  2061   font-variant: normal;
  2062   font-weight: 600;
  2063   font-size: 9pt;
  2064   line-height: normal;
  2065   font-family: Charcoal
  2067 </pre>
  2068   </div>
  2069   <!-- prop: font-synthesis -->
  2071   <h3 id=font-synthesis-prop><span class=secno>3.8 </span>Controlling
  2072    synthetic faces: the <a href="#propdef-font-synthesis">font-synthesis</a>
  2073    property</h3>
  2075   <table class=propdef id=namefont-synthesisvaluenone-weight-style>
  2076    <tbody>
  2077     <tr>
  2078      <td>Name:
  2080      <td><dfn id=propdef-font-synthesis>font-synthesis</dfn>
  2082     <tr>
  2083      <td>Value:
  2085      <td>none | [ weight || style ]
  2087     <tr>
  2088      <td>Initial:
  2090      <td>weight style
  2092     <tr>
  2093      <td>Applies to:
  2095      <td>all elements
  2097     <tr>
  2098      <td>Inherited:
  2100      <td>yes
  2102     <tr>
  2103      <td>Percentages:
  2105      <td>N/A
  2107     <tr>
  2108      <td>Media:
  2110      <td>visual
  2112     <tr>
  2113      <td>Computed value:
  2115      <td>as specified
  2117     <tr>
  2118      <td>Animatable:
  2120      <td>no
  2121   </table>
  2123   <p>This property controls whether user agents are allowed to synthesize
  2124    bold or oblique font faces when a font family lacks bold or italic faces.
  2125    If ‘<a href="#weight"><code class=property>weight</code></a>’ is not
  2126    specified, user agents must not synthesize bold faces and if ‘<code
  2127    class=property>style</code>’ is not specified user agents must not
  2128    synthesize italic faces. A value of ‘<code class=property>none</code>’
  2129    disallows all synthetic faces.
  2131   <div class=example>
  2132    <p>The style rule below disables the use of synthetically obliqued Arabic:</p>
  2134    <pre>*:lang(ar) { font-synthesis: none; }
  2135 </pre>
  2136   </div>
  2138   <h2 id=font-resources><span class=secno>4 </span>Font Resources</h2>
  2140   <h3 id=font-face-rule><span class=secno>4.1 </span>The <dfn
  2141    id=at-font-face-rule style="font-weight: inherit; font-style:
  2142    inherit"><code>@font-face</code></dfn> rule</h3>
  2144   <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule allows
  2145    for linking to fonts that are automatically fetched and activated when
  2146    needed. This allows authors to select a font that closely matches the
  2147    design goals for a given page rather than limiting the font choice to a
  2148    set of fonts available on all platforms. A set of font descriptors define
  2149    the location of a font resource, either locally or externally, along with
  2150    the style characteristics of an individual face. Multiple <a
  2151    href="#at-font-face-rule"><code>@font-face</code></a> rules can be used to
  2152    construct font families with a variety of faces. Using CSS font matching
  2153    rules, a user agent can selectively download only those faces that are
  2154    needed for a given piece of text.
  2156   <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule
  2157    consists of the <a href="#at-font-face-rule"><code>@font-face</code></a>
  2158    at-keyword followed by a block of descriptor declarations. In terms of the
  2159    grammar, this specification defines the following productions:
  2161   <pre><dfn id=fontfacerule>font_face_rule</dfn>
  2162   : <a href="#fontfacesym"><i>FONT_FACE_SYM</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#descriptordeclaration"><i>descriptor_declaration</i></a>? [ ';' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#descriptordeclaration"><i>descriptor_declaration</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
  2165 <dfn id=descriptordeclaration>descriptor_declaration</dfn>
  2166   : <a href="http://www.w3.org/TR/CSS21/grammar.html#grammar"><i>property</i></a> ':' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/grammar.html#grammar"><i>expr</i></a>
  2167   ;</pre>
  2169   <p>The following new definitions are introduced:
  2171   <pre>-    -|\\0{0,4}2d(\r\n|[ \t\r\n\f])?
  2172 F    f|\\0{0,4}(46|66)(\r\n|[ \t\r\n\f])?</pre>
  2174   <p>The following new token is introduced:
  2176   <pre>@{F}{O}{N}{T}{-}{F}{A}{C}{E} {return <dfn id=fontfacesym>FONT_FACE_SYM</dfn>;}</pre>
  2178   <p>Each <a href="#at-font-face-rule"><code>@font-face</code></a> rule
  2179    specifies a value for every font descriptor, either implicitly or
  2180    explicitly. Those not given explicit values in the rule take the initial
  2181    value listed with each descriptor in this specification. These descriptors
  2182    apply solely within the context of the <a
  2183    href="#at-font-face-rule"><code>@font-face</code></a> rule in which they
  2184    are defined, and do not apply to document language elements. There is no
  2185    notion of which elements the descriptors apply to or whether the values
  2186    are inherited by child elements. When a given descriptor occurs multiple
  2187    times in a given <a href="#at-font-face-rule"><code>@font-face</code></a>
  2188    rule, only the last descriptor declaration is used and all prior
  2189    declarations for that descriptor are ignored.
  2191   <div class=example>
  2192    <p>To use a downloadable font called Gentium:</p>
  2194    <pre>
  2195 @font-face {
  2196   font-family: Gentium;
  2197   src: url(http://example.com/fonts/Gentium.ttf);
  2200 p { font-family: Gentium, serif; }
  2201 </pre>
  2203    <p>The user agent will download Gentium and use it when rendering text
  2204     within paragraph elements. If for some reason the site serving the font
  2205     is unavailable, the default serif font will be used.</p>
  2206   </div>
  2208   <p>A given set of <a href="#at-font-face-rule"><code>@font-face</code></a>
  2209    rules define a set of fonts available for use within the documents that
  2210    contain these rules. When font matching is done, fonts defined using these
  2211    rules are considered before other available fonts on a system.
  2213   <p>Downloaded fonts are only available to documents that reference them.
  2214    The process of activating these fonts must not make them available to
  2215    other applications or to documents that don't directly link to the same
  2216    font. User agent implementers might consider it convenient to use
  2217    downloaded fonts when rendering characters in other documents for which no
  2218    other available font exists as part of the <a
  2219    href="#system-font-fallback"><em>system font fallback</em></a> procedure.
  2220    However, this would cause a security leak since the contents of one page
  2221    would be able to affect other pages, something an attacker could use as an
  2222    attack vector. These restrictions do not affect caching behavior, fonts
  2223    are cached the same way other web resources are cached.
  2225   <p>This at-rule follows the forward-compatible parsing rules of CSS. Like
  2226    properties in a declaration block, declarations of any descriptors that
  2227    are not supported by the user agent must be ignored. <a
  2228    href="#at-font-face-rule"><code>@font-face</code></a> rules require a
  2229    font-family and src descriptor; if either of these are missing, the <a
  2230    href="#at-font-face-rule"><code>@font-face</code></a> rule is invalid and
  2231    must be ignored entirely.
  2233   <p>In cases where user agents have limited platform resources or implement
  2234    the ability to disable downloadable font resources, <a
  2235    href="#at-font-face-rule"><code>@font-face</code></a> rules must simply be
  2236    ignored; the behavior of individual descriptors as defined in this
  2237    specification should not be altered.
  2239   <h3 id=font-family-desc><span class=secno>4.2 </span>Font family: the <a
  2240    href="#descdef-font-family">font-family</a> descriptor</h3>
  2242   <table class=descdef>
  2243    <tbody>
  2244     <tr>
  2245      <td>Name:
  2247      <td><dfn id=descdef-font-family
  2248       title="font-family!!descriptor">font-family</dfn>
  2250     <tr>
  2251      <td>Value:
  2253      <td><a href="#family-name-value"><var>&lt;family-name&gt;</var></a>
  2255     <tr>
  2256      <td><em>Initial:</em>
  2258      <td>N/A
  2259   </table>
  2261   <p>This descriptor defines the font family name that will be used in all
  2262    CSS font family name matching. It is required for the <a
  2263    href="#at-font-face-rule"><code>@font-face</code></a> rule to be valid. It
  2264    overrides the font family names contained in the underlying font data. If
  2265    the font family name is the same as a font family available in a given
  2266    user's environment, it effectively hides the underlying font for documents
  2267    that use the stylesheet. This permits a web author to freely choose
  2268    font-family names without worrying about conflicts with font family names
  2269    present in a given user's environment. Likewise, platform substitutions
  2270    for a given font family name must not be used.
  2272   <h3 id=src-desc><span class=secno>4.3 </span>Font reference: the <a
  2273    href="#descdef-src">src</a> descriptor</h3>
  2275   <table class=descdef>
  2276    <tbody>
  2277     <tr>
  2278      <td>Name:
  2280      <td><dfn id=descdef-src>src</dfn>
  2282     <tr>
  2283      <td>Value:
  2285      <td>[ &lt;url> [format(&lt;string> #)]? | <a
  2286       href="#font-face-name-value"><var>&lt;font-face-name&gt;</var></a> ] #
  2288     <tr>
  2289      <td><em>Initial:</em>
  2291      <td>N/A
  2292   </table>
  2294   <p>This descriptor specifies the resource containing font data. It is
  2295    required for the <a href="#at-font-face-rule"><code>@font-face</code></a>
  2296    rule to be valid. Its value is a prioritized, comma-separated list of
  2297    external references or locally-installed font face names. When a font is
  2298    needed the user agent iterates over the set of references listed, using
  2299    the first one it can successfully activate. Fonts containing invalid data
  2300    or local font faces that are not found are ignored and the user agent
  2301    loads the next font in the list.
  2303   <p>As with other URLs in CSS, the URL may be relative, in which case it is
  2304    resolved relative to the location of the style sheet containing the <a
  2305    href="#at-font-face-rule"><code>@font-face</code></a> rule. In the case of
  2306    SVG fonts, the URL points to an element within a document containing SVG
  2307    font definitions. If the element reference is omitted, a reference to the
  2308    first defined font is implied. Similarly, font container formats that can
  2309    contain more than one font must load one and only one of the fonts for a
  2310    given <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
  2311    Fragment identifiers are used to indicate which font to load. If a
  2312    container format lacks a defined fragment identifier scheme,
  2313    implementations should use a simple 1-based indexing scheme (e.g.
  2314    "font-collection#1" for the first font, "font-collection#2" for the second
  2315    font).
  2317   <pre>
  2318 src: url(fonts/simple.ttf);   /* load simple.ttf relative to stylesheet location */
  2319 src: url(/fonts/simple.ttf);  /* load simple.ttf from absolute location */
  2320 src: url(fonts.svg#simple);   /* load SVG font with id 'simple' */
  2321 </pre>
  2323   <p>External references consist of a URL, followed by an optional hint
  2324    describing the format of the font resource referenced by that URL. The
  2325    format hint contains a comma-separated list of format strings that denote
  2326    well-known font formats. Conformant user agents must skip downloading a
  2327    font resource if the format hints indicate only unsupported or unknown
  2328    font formats. If no format hints are supplied, the user agent should
  2329    download the font resource.
  2331   <pre>
  2332 /* load WOFF font if possible, otherwise use OpenType font */
  2333 @font-face {
  2334   font-family: bodytext;
  2335   src: url(ideal-sans-serif.woff) format("woff"),
  2336        url(basic-sans-serif.ttf) format("opentype");
  2338 </pre>
  2340   <p>Format strings defined by this specification:
  2342   <table class=data id=fontformats>
  2343    <thead>
  2344     <tr>
  2345      <th>String
  2347      <th>Font Format
  2349      <th>Common extensions
  2351    <tbody>
  2352     <tr>
  2353      <th>"woff"
  2355      <td><a href="http://www.w3.org/TR/WOFF/">WOFF (Web Open Font Format)</a>
  2357      <td>.woff
  2359     <tr>
  2360      <th>"truetype"
  2362      <td><a
  2363       href="http://www.microsoft.com/typography/otspec/default.htm">TrueType</a>
  2365      <td>.ttf
  2367     <tr>
  2368      <th>"opentype"
  2370      <td><a
  2371       href="http://www.microsoft.com/typography/otspec/default.htm">OpenType</a>
  2373      <td>.ttf, .otf
  2375     <tr>
  2376      <th>"embedded-opentype"
  2378      <td><a
  2379       href="http://www.w3.org/Submission/2008/SUBM-EOT-20080305/">Embedded
  2380       OpenType</a>
  2382      <td>.eot
  2384     <tr>
  2385      <th>"svg"
  2387      <td><a href="http://www.w3.org/TR/SVG/fonts.html">SVG Font</a>
  2389      <td>.svg, .svgz
  2390   </table>
  2392   <p>Given the overlap in common usage between TrueType and OpenType, the
  2393    format hints "truetype" and "opentype" must be considered as synonymous; a
  2394    format hint of "opentype" does not imply that the font contains Postscript
  2395    CFF style glyph data or that it contains OpenType layout information (see
  2396    <a href="#platform-props-to-css">Appendix A</a> for more background on
  2397    this).
  2399   <p>When authors would prefer to use a locally available copy of a given
  2400    font and download it if it's not, <code>local()</code> can be used. The
  2401    locally-installed <dfn
  2402    id=font-face-name-value><var>&lt;font-face-name&gt;</var></dfn> argument
  2403    to <code>local()</code> is a format-specific string that uniquely
  2404    identifies a single font face within a larger family. The syntax for a <a
  2405    href="#font-face-name-value"><var>&lt;font-face-name&gt;</var></a> is a
  2406    unique font face name enclosed by "local(" and ")". The name can
  2407    optionally be enclosed in quotes. If unquoted, the unquoted font family
  2408    name processing conventions apply; the name must be a sequence of
  2409    identifiers separated by whitespace which is converted to a string by
  2410    joining the identifiers together separated by a single space.
  2412   <pre>
  2413 /* regular face of Gentium */
  2414 @font-face {
  2415   font-family: MyGentium;
  2416   src: local(Gentium),   /* use locally available Gentium */
  2417        url(Gentium.ttf); /* otherwise, download it */
  2419 </pre>
  2421   <p>For OpenType and TrueType fonts, this string is used to match only the
  2422    Postscript name or the full font name in the name table of locally
  2423    available fonts. Which type of name is used varies by platform and font,
  2424    so authors should include both of these names to assure proper matching
  2425    across platforms. Platform substitutions for a given font name must not be
  2426    used.
  2428   <pre>
  2429 /* bold face of Gentium */
  2430 @font-face {
  2431   font-family: MyGentium;
  2432   src: local(Gentium Bold),   /* full font name */
  2433        local(Gentium-Bold),   /* Postscript name */
  2434        url(GentiumBold.ttf);  /* otherwise, download it */
  2435   font-weight: bold;
  2437 </pre>
  2439   <p>Just as a <a href="#at-font-face-rule"><code>@font-face</code></a> rule
  2440    specifies the characteristics of a single font within a family, the unique
  2441    name used with <code>local()</code> specifies a single font, not an entire
  2442    font family. Defined in terms of OpenType font data, the Postscript name
  2443    is found in the font's <a
  2444    href="http://www.microsoft.com/typography/otspec/name.htm">name table</a>,
  2445    in the name record with nameID = 6 (see <a href="#OPENTYPE"
  2446    rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> for more details). The
  2447    Postscript name is the commonly used key for all fonts on OSX and for
  2448    Postscript CFF fonts under Windows. The full font name (nameID = 4) is
  2449    used as a unique key for fonts with TrueType glyphs on Windows.
  2451   <p>For OpenType fonts with multiple localizations of the full font name,
  2452    the US English version is used (language ID = 0x409 for Windows and
  2453    language ID = 0 for Macintosh) or the first localization when a US English
  2454    full font name is not available (the OpenType specification recommends
  2455    that <a href="http://www.microsoft.com/typography/otspec/recom.htm">all
  2456    fonts minimally include US English names</a>). User agents that also match
  2457    other full font names, e.g. matching the Dutch name when the current
  2458    system locale is set to Dutch, are considered non-conformant. This is done
  2459    not to prefer English but to avoid matching inconsistencies across font
  2460    versions and OS localizations, since font style names (e.g. "Bold") are
  2461    frequently localized into many languages and the set of localizations
  2462    available varies widely across platform and font version. User agents that
  2463    match a concatenation of family name (nameID = 1) with style name (nameID
  2464    = 2) are considered non-conformant.
  2466   <p>This also allows for referencing faces that belong to larger families
  2467    that cannot otherwise be referenced.
  2469   <div class=example>
  2470    <p>Use a local font or reference an SVG font in another document:</p>
  2472    <pre>
  2473 @font-face {
  2474   font-family: Headline;
  2475   src: local(Futura-Medium),
  2476        url(fonts.svg#MyGeometricModern) format("svg");
  2478 </pre>
  2480    <p>Create an alias for local Japanese fonts on different platforms:</p>
  2482    <pre>
  2483 @font-face {
  2484   font-family: jpgothic;
  2485   src: local(HiraKakuPro-W3), local(Meiryo), local(IPAPGothic);
  2487 </pre>
  2489    <p>Reference a font face that cannot be matched within a larger family:</p>
  2491    <pre>
  2492 @font-face {
  2493   font-family: Hoefler Text Ornaments;
  2494   /* has the same font properties as Hoefler Text Regular */
  2495   src: local(HoeflerText-Ornaments);
  2497 </pre>
  2499    <p>Since localized fullnames never match, a document with the header style
  2500     rules below would always render using the default serif font, regardless
  2501     whether a particular system locale parameter is set to Finnish or not:</p>
  2503    <pre>
  2504 @font-face {
  2505   font-family: SectionHeader;
  2506   src: local("Arial Lihavoitu");  /* Finnish fullname for Arial Bold, should fail */
  2507   font-weight: bold;
  2510 h2 { font-family: SectionHeader, serif; }
  2511 </pre>
  2513    <p>A conformant user agent would never load the font ‘<code
  2514     class=css>gentium.eot</code>’ in the example below, since it is
  2515     included in the first definition of the ‘<a href="#descdef-src"><code
  2516     class=property>src</code></a>’ descriptor which is overridden by the
  2517     second definition in the same <a
  2518     href="#at-font-face-rule"><code>@font-face</code></a> rule:</p>
  2520    <pre>
  2521 @font-face {
  2522   font-family: MainText;
  2523   src: url(gentium.eot); /* for use with older non-conformant user agents */
  2524   src: local("Gentium"), url(gentium.ttf);  /* Overrides src definition */
  2526 </pre>
  2527   </div>
  2529   <h3 id=font-prop-desc><span class=secno>4.4 </span>Font property
  2530    descriptors: the <a href="#descdef-font-style">font-style</a>, <a
  2531    href="#descdef-font-weight">font-weight</a>, <a
  2532    href="#descdef-font-stretch">font-stretch</a> descriptors</h3>
  2534   <table class=descdef>
  2535    <tbody>
  2536     <tr>
  2537      <td>Name:
  2539      <td><dfn id=descdef-font-style
  2540       title="font-style!!descriptor">font-style</dfn>
  2542     <tr>
  2543      <td>Value:
  2545      <td>normal | italic | oblique
  2547     <tr>
  2548      <td><em>Initial:</em>
  2550      <td>normal
  2551   </table>
  2553   <table class=descdef>
  2554    <tbody>
  2555     <tr>
  2556      <td>Name:
  2558      <td><dfn id=descdef-font-weight
  2559       title="font-weight!!descriptor">font-weight</dfn>
  2561     <tr>
  2562      <td>Value:
  2564      <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
  2566     <tr>
  2567      <td><em>Initial:</em>
  2569      <td>normal
  2570   </table>
  2572   <table class=descdef>
  2573    <tbody>
  2574     <tr>
  2575      <td>Name:
  2577      <td><dfn id=descdef-font-stretch
  2578       title="font-stretch!!descriptor">font-stretch</dfn>
  2580     <tr>
  2581      <td>Value:
  2583      <td>normal | ultra-condensed | extra-condensed | condensed |
  2584       semi-condensed | semi-expanded | expanded | extra-expanded |
  2585       ultra-expanded
  2587     <tr>
  2588      <td><em>Initial:</em>
  2590      <td>normal
  2591   </table>
  2593   <p>These descriptors define the characteristics of a font face and are used
  2594    in the process of matching styles to specific faces. For a font family
  2595    defined with several <a
  2596    href="#at-font-face-rule"><code>@font-face</code></a> rules, user agents
  2597    can either download all faces in the family or use these descriptors to
  2598    selectively download font faces that match actual styles used in document.
  2599    The values for these descriptors are the same as those for the
  2600    corresponding font properties except that relative keywords are not
  2601    allowed, ‘<a href="#bolder"><code class=property>bolder</code></a>’
  2602    and ‘<a href="#lighter"><code class=property>lighter</code></a>’. If
  2603    these descriptors are omitted, initial values are assumed.
  2605   <p>The value for these font face style attributes is used in place of the
  2606    style implied by the underlying font data. This allows authors to combine
  2607    faces in flexible combinations, even in situations where the original font
  2608    data was arranged differently. User agents that implement synthetic
  2609    bolding and obliquing must only apply synthetic styling in cases where the
  2610    font descriptors imply this is needed, rather than based on the style
  2611    attributes implied by the font data.
  2613   <h3 id=unicode-range-desc><span class=secno>4.5 </span>Character range: the
  2614    <a href="#descdef-unicode-range">unicode-range</a> descriptor</h3>
  2616   <table class=descdef>
  2617    <tbody>
  2618     <tr>
  2619      <td>Name:
  2621      <td><dfn id=descdef-unicode-range>unicode-range</dfn>
  2623     <tr>
  2624      <td>Value:
  2626      <td><a href="#urange-value"><var>&lt;urange&gt;</var></a> #
  2628     <tr>
  2629      <td><em>Initial:</em>
  2631      <td>U+0-10FFFF
  2632   </table>
  2634   <p>This descriptor defines the set of Unicode codepoints that may be
  2635    supported by the font face for which it is declared. The descriptor value
  2636    is a comma-delimited list of Unicode range (<a
  2637    href="#urange-value"><var>&lt;urange&gt;</var></a>) values. The union of
  2638    these ranges defines the set of codepoints that serves as a hint for user
  2639    agents when deciding whether or not to download a font resource for a
  2640    given text run.
  2642   <p>Each <dfn id=urange-value><var>&lt;urange&gt;</var></dfn> value is a <a
  2643    href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
  2644    title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token made up of a
  2645    "U+" or "u+" prefix followed by a codepoint range in one of the three
  2646    forms listed below. Ranges that do not fit one of the these forms are
  2647    invalid and cause the declaration to be ignored.
  2649   <dl>
  2650    <dt>single codepoint (e.g. U+416)
  2652    <dd>a valid Unicode codepoint, represented as one to six hexadecimal
  2653     digits
  2655    <dt>interval range (e.g. U+400-4ff)
  2657    <dd>represented as two hyphen-separated valid Unicode codepoints
  2658     indicating the inclusive start and end codepoints of a range
  2660    <dt>wildcard range (e.g. U+4??)
  2662    <dd>defined by the set of codepoints implied when trailing ‘<code
  2663     class=css>?</code>’ characters signify any hexadeximal digit
  2664   </dl>
  2666   <p>Individual codepoints are written using hexadecimal values that
  2667    correspond to <a href="http://www.unicode.org/charts/">Unicode character
  2668    codepoints</a>. Valid Unicode codepoint values vary between 0 and 10FFFF
  2669    inclusive. Digit values of codepoints are ASCII case-insensitive. For
  2670    interval ranges, the start and end codepoints are valid Unicode values and
  2671    the end codepoint is greater than or equal to the start codepoint.
  2673   <p>Wildcard ranges specified with ‘?’ that lack an initial digit (e.g.
  2674    "U+???") are valid and equivalent to a wildcard range with an initial zero
  2675    digit (e.g. "U+0???" = "U+0000-0FFF"). Wildcard ranges that extend beyond
  2676    the range of valid Unicode codepoints are invalid. Because of this, the
  2677    maximum number of trailing ‘<code class=css>?</code>’ wildcard
  2678    characters is five, even though the <a
  2679    href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
  2680    title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token accepts six.
  2682   <p>Within the comma-delimited list of Unicode ranges in a ‘<a
  2683    href="#descdef-unicode-range"><code
  2684    class=property>unicode-range</code></a>’ descriptor declaration, ranges
  2685    may overlap. The union of these ranges defines the set of codepoints for
  2686    which the corresponding font may be used. User agents must not download or
  2687    use the font for codepoints outside this set. User agents may normalize
  2688    the list of ranges into a list that is different but represents the same
  2689    set of codepoints.
  2691   <p>The associated font might not contain glyphs for the entire set of
  2692    codepoints defined by the ‘<a href="#descdef-unicode-range"><code
  2693    class=property>unicode-range</code></a>’ descriptor. When the font is
  2694    used the effective <a href="#character-map"><em>character map</em></a> is
  2695    the intersection of the codepoints defined by ‘<a
  2696    href="#descdef-unicode-range"><code
  2697    class=property>unicode-range</code></a>’ with the font's <a
  2698    href="#character-map"><em>character map</em></a>. This allows authors to
  2699    define supported ranges in terms of broad ranges without worrying about
  2700    the precise codepoint ranges supported by the underlying font.
  2702   <h3 id=composite-fonts><span class=secno>4.6 </span>Using character ranges
  2703    to define composite fonts</h3>
  2705   <p>Multiple <a href="#at-font-face-rule"><code>@font-face</code></a> rules
  2706    with different unicode ranges for the same family and style descriptor
  2707    values can be used to create composite fonts that mix the glyphs from
  2708    different fonts for different scripts. This can be used to combine fonts
  2709    that only contain glyphs for a single script (e.g. Latin, Greek, Cyrillic)
  2710    or it can be used by authors as a way of segmenting a font into fonts for
  2711    commonly used characters and less frequently used characters. Since the
  2712    user agent will only pull down the fonts it needs this helps reduce page
  2713    bandwidth.
  2715   <p>If the unicode ranges overlap for a set of <a
  2716    href="#at-font-face-rule"><code>@font-face</code></a> rules with the same
  2717    family and style descriptor values, the rules are ordered in the reverse
  2718    order they were defined; the last rule defined is the first to be checked
  2719    for a given character.
  2721   <p>Example ranges for specific languages or characters:
  2723   <dl>
  2724    <dt>unicode-range: U+A5;
  2726    <dd>a single code point, the yen/yuan symbol
  2728    <dt>unicode-range: U+0-7F;
  2730    <dd>code range for basic ASCII characters
  2732    <dt>unicode-range: U+590-5ff;
  2734    <dd>code range for Hebrew characters
  2736    <dt>unicode-range: U+A5, U+4E00-9FFF, U+30??, U+FF00-FF9F;
  2738    <dd>code range for Japanese kanji, hiragana and katakana characters plus
  2739     yen/yuan symbol
  2740   </dl>
  2742   <div class=example>
  2743    <p>The BBC provides news services in a wide variety of languages, many
  2744     that are not well supported across all platforms. Using an <a
  2745     href="#at-font-face-rule"><code>@font-face</code></a> rule, the BBC could
  2746     provide a font for any of these languages, as it already does via a
  2747     manual font download.</p>
  2749    <pre>
  2750 @font-face {
  2751   font-family: BBCBengali;
  2752   src: url(fonts/BBCBengali.ttf) format("opentype");
  2753   unicode-range: U+00-FF, U+980-9FF;
  2755 </pre>
  2756   </div>
  2758   <div class=example>
  2759    <p>Technical documents often require a wide range of symbols. The STIX
  2760     Fonts project is one project aimed at providing fonts to support a wide
  2761     range of technical typesetting in a standardized way. The example below
  2762     shows the use of a font that provides glyphs for many of the mathematical
  2763     and technical symbol ranges within Unicode:</p>
  2765    <pre>
  2766 @font-face {
  2767   font-family: STIXGeneral;
  2768   src: local(STIXGeneral), url(/stixfonts/STIXGeneral.otf);
  2769   unicode-range: U+000-49F, U+2000-27FF, U+2900-2BFF, U+1D400-1D7FF;
  2771 </pre>
  2772   </div>
  2774   <div class=example>
  2775    <p>This example shows how an author can override the glyphs used for Latin
  2776     characters in a Japanese font with glyphs from a different font. The
  2777     first rule specifies no range so it defaults to the entire range. The
  2778     range specified in the second rule overlaps but takes precedence because
  2779     it is defined later.</p>
  2781    <pre>
  2782 @font-face {
  2783   font-family: JapaneseWithGentium;
  2784   src: local(MSMincho);
  2785   /* no range specified, defaults to entire range */
  2788 @font-face {
  2789   font-family: JapaneseWithGentium;
  2790   src: url(../fonts/Gentium.ttf);
  2791   unicode-range: U+0-2FF;
  2793 </pre>
  2794   </div>
  2796   <div class=example>
  2797    <p>Consider a family constructed to optimize bandwidth by separating out
  2798     Latin, Japanese and other characters into different font files:</p>
  2800    <pre>
  2801 /* fallback font - size: 4.5MB */
  2802 @font-face {
  2803   font-family: DroidSans;
  2804   src: url(DroidSansFallback.ttf);
  2805   /* no range specified, defaults to entire range */
  2808 /* Japanese glyphs - size: 1.2MB */
  2809 @font-face {
  2810   font-family: DroidSans;
  2811   src: url(DroidSansJapanese.ttf);
  2812   unicode-range: U+3000-9FFF, U+ff??;
  2815 /* Latin, Greek, Cyrillic along with some
  2816    punctuation and symbols - size: 190KB */
  2817 @font-face {
  2818   font-family: DroidSans;
  2819   src: url(DroidSans.ttf);
  2820   unicode-range: U+000-5FF, U+1e00-1fff, U+2000-2300;
  2822 </pre>
  2824    <p>For simple Latin text, only the font for Latin characters is
  2825     downloaded:</p>
  2827    <pre>
  2828 body { font-family: DroidSans; }
  2830 &lt;p>This is that&lt;/p>
  2831 </pre>
  2833    <p>In this case the user agent first checks the unicode-range for the font
  2834     containing Latin characters (DroidSans.ttf). Since all the characters
  2835     above are in the range U+0-5FF, the user agent downloads the font and
  2836     renders the text with that font.</p>
  2838    <p>Next, consider text that makes use of an arrow character (⇨):</p>
  2840    <pre>
  2841 &lt;p>This &amp;#x21e8; that&lt;p>
  2842 </pre>
  2844    <p>The user agent again first checks the unicode-range of the font
  2845     containing Latin characters. Since U+2000-2300 includes the arrow code
  2846     point (U+21E8), the user agent downloads the font. For this character
  2847     however the Latin font does not have a matching glyph, so the effective
  2848     unicode-range used for font matching excludes this code point. Next, the
  2849     user agent evaluates the Japanese font. The unicode-range for the
  2850     Japanese font, U+3000-9FFF and U+ff??, does not include U+21E8, so the
  2851     user agent does not download the Japanese font. Next the fallback font is
  2852     considered. The <a href="#at-font-face-rule"><code>@font-face</code></a>
  2853     rule for the fallback font does not define unicode-range so its value
  2854     defaults to the range of all Unicode code points. The fallback font is
  2855     downloaded and used to render the arrow character.</p>
  2856   </div>
  2858   <h3 id=font-rend-desc><span class=secno>4.7 </span>Font features: the <a
  2859    href="#descdef-font-variant">font-variant</a> and <a
  2860    href="#descdef-font-feature-settings">font-feature-settings</a>
  2861    descriptors</h3>
  2863   <table class=descdef>
  2864    <tbody>
  2865     <tr>
  2866      <td>Name:
  2868      <td><dfn id=descdef-font-variant
  2869       title="font-variant!!descriptor">font-variant</dfn>
  2871     <tr>
  2872      <td>Value:
  2874      <td><a href="#font-variant-normal-value"
  2875       title="normal!!font-variant">normal</a> | <a
  2876       href="#font-variant-none-value" title="none!!font-variant">none</a> | [
  2877       <a href="#common-lig-values"><var>&lt;common-lig-values&gt;</var></a>
  2878       || <a
  2879       href="#discretionary-lig-values"><var>&lt;discretionary-lig-values&gt;</var></a>
  2880       || <a
  2881       href="#historical-lig-values"><var>&lt;historical-lig-values&gt;</var></a>
  2882       || <a
  2883       href="#contextual-alt-values"><var>&lt;contextual-alt-values&gt;</var></a>
  2884       || <a href="#stylistic"><var
  2885       title=stylistic>stylistic(&lt;feature-value-name&gt;)</var></a> || <a
  2886       href="#historical-forms"><var>historical-forms</var></a> || <a
  2887       href="#styleset"><var
  2888       title=styleset>styleset(&lt;feature-value-name&gt; #)</var></a> || <a
  2889       href="#character-variant"><var
  2890       title=character-variant>character-variant(&lt;feature-value-name&gt;
  2891       #)</var></a> || <a href="#swash"><var
  2892       title=swash>swash(&lt;feature-value-name&gt;)</var></a> || <a
  2893       href="#ornaments"><var
  2894       title=ornaments>ornaments(&lt;feature-value-name&gt;)</var></a> || <a
  2895       href="#annotation"><var
  2896       title=annotation>annotation(&lt;feature-value-name&gt;)</var></a> || [
  2897       <a href="#small-caps"><i>small-caps</i></a> | <a
  2898       href="#all-small-caps"><i>all-small-caps</i></a> | <a
  2899       href="#petite-caps"><i>petite-caps</i></a> | <a
  2900       href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
  2901       href="#unicase"><i>unicase</i></a> | <a
  2902       href="#titling-caps"><i>titling-caps</i></a> ] || <a
  2903       href="#numeric-figure-values"><var>&lt;numeric-figure-values&gt;</var></a>
  2904       || <a
  2905       href="#numeric-spacing-values"><var>&lt;numeric-spacing-values&gt;</var></a>
  2906       || <a
  2907       href="#numeric-fraction-values"><var>&lt;numeric-fraction-values&gt;</var></a>
  2908       || <a href="#ordinal"><i>ordinal</i></a> || <a
  2909       href="#slashed-zero"><i>slashed-zero</i></a> || <a
  2910       href="#east-asian-variant-values"><var>&lt;east-asian-variant-values&gt;</var></a>
  2911       || <a
  2912       href="#east-asian-width-values"><var>&lt;east-asian-width-values&gt;</var></a>
  2913       || <a href="#ruby"><i>ruby</i></a> ]
  2915     <tr>
  2916      <td><em>Initial:</em>
  2918      <td>normal
  2919   </table>
  2921   <table class=descdef>
  2922    <tbody>
  2923     <tr>
  2924      <td>Name:
  2926      <td><dfn id=descdef-font-feature-settings
  2927       title="font-feature-settings!!descriptor">font-feature-settings</dfn>
  2929     <tr>
  2930      <td>Value:
  2932      <td><a href="#font-feature-settings-normal-value"
  2933       title="normal!!font-feature-settings">normal</a> | <a
  2934       href="#feature-tag-value"><var>&lt;feature-tag-value&gt;</var></a> #
  2936     <tr>
  2937      <td><em>Initial:</em>
  2939      <td>normal
  2940   </table>
  2942   <p>These descriptors define initial settings that apply when the font
  2943    defined by an <a href="#at-font-face-rule"><code>@font-face</code></a>
  2944    rule is rendered. They do not affect font selection. Values are identical
  2945    to those defined for the corresponding <a href="#propdef-font-variant"
  2946    title="font-variant!!property">‘<code
  2947    class=property>font-variant</code>’</a> and <a
  2948    href="#propdef-font-feature-settings"
  2949    title="font-feature-settings!!property">‘<code
  2950    class=property>font-feature-settings</code>’</a> properties defined
  2951    below except that the value ‘<code class=property>inherit</code>’ is
  2952    omitted. When multiple font feature descriptors or properties are used,
  2953    the cumulative effect on text rendering is detailed in the section <a
  2954    href="#font-feature-resolution">Font Feature Resolution</a> below. In
  2955    cases where specific values define synthesized fallback for certain <a
  2956    href="#propdef-font-variant" title="font-variant!!property">‘<code
  2957    class=property>font-variant</code>’</a> subproperties, the same
  2958    synthesized fallback applies when used within those values are used with
  2959    the <a href="#descdef-font-style" title="font-style!!descriptor">‘<code
  2960    class=property>font-variant</code>’</a> descriptor.
  2962   <h3 id=font-face-loading><span class=secno>4.8 </span>Font loading
  2963    guidelines</h3>
  2965   <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule is
  2966    designed to allow lazy loading of font resources that are only downloaded
  2967    when used within a document. A stylesheet can include <a
  2968    href="#at-font-face-rule"><code>@font-face</code></a> rules for a library
  2969    of fonts of which only a select set are used; user agents must only
  2970    download those fonts that are referred to within the style rules
  2971    applicable to a given page. User agents that download all fonts defined in
  2972    <a href="#at-font-face-rule"><code>@font-face</code></a> rules without
  2973    considering whether those fonts are in fact used within a page are
  2974    considered non-conformant. In cases where a font might be downloaded in
  2975    character fallback cases, user agents may download a font if it's
  2976    contained within the computed value of <a href="#propdef-font-family"
  2977    title="font-family!!property">‘<code
  2978    class=property>font-family</code>’</a> for a given text run.
  2980   <pre>
  2981 @font-face {
  2982   font-family: GeometricModern;
  2983   src: url(font.ttf);
  2986 p {
  2987   /* font will be downloaded for pages with p elements */
  2988   font-family: GeometricModern, sans-serif;
  2991 h2 {
  2992   /* font may be downloaded for pages with h2 elements, even if Futura is available locally */
  2993   font-family: Futura, GeometricModern, sans-serif;
  2995 </pre>
  2997   <p>In cases where textual content is loaded before downloadable fonts are
  2998    available, user agents may render text as it would be rendered if
  2999    downloadable font resources are not available or they may render text
  3000    transparently with fallback fonts to avoid a flash of text using a
  3001    fallback font. In cases where the font download fails user agents must
  3002    display text, simply leaving transparent text is considered non-conformant
  3003    behavior. Authors are advised to use fallback fonts in their font lists
  3004    that closely match the vertical metrics of the downloadable fonts to avoid
  3005    large page reflows where possible.
  3007   <h3 id=same-origin-restriction><span class=secno>4.9 </span>Same-origin
  3008    restriction for fonts</h3>
  3010   <h4 id=default-same-origin-restriction><span class=secno>4.9.1
  3011    </span>Default same-origin restriction</h4>
  3012   <!-- TPAC 2011 Resolution to require same-origin restriction for loading fonts:
  3013   http://lists.w3.org/Archives/Public/www-style/2011Nov/0711.html
  3014   http://www.w3.org/2011/10/31-webapps-minutes.html#item02
  3015 -->
  3017   <p>User agents must implement a same-origin restriction when loading fonts
  3018    via the <a href="#at-font-face-rule"><code>@font-face</code></a>
  3019    mechanism. This restriction limits the loading of fonts for a given
  3020    document to fonts loaded from the same origin. Fonts can only be loaded
  3021    via the same host, port, and method combination as the containing
  3022    document, using the <a
  3023    href="http://www.w3.org/TR/html5/browsers.html#origin">origin matching
  3024    algorithm</a> described in the <a href="#HTML5"
  3025    rel=biblioentry>[HTML5]<!--{{!HTML5}}--></a> specification. The origin of
  3026    the stylesheet containing <a
  3027    href="#at-font-face-rule"><code>@font-face</code></a> rules is not used
  3028    when deciding whether a font is same origin or not, only the origin of the
  3029    containing document is used. The restriction applies to all font types.
  3031   <p>Given a document located at http://example.com/page.html, fonts defined
  3032    with ‘<a href="#descdef-src"><code class=property>src</code></a>’
  3033    definitions considered cross origin must not be loaded:
  3035   <pre>
  3036 /* same origin (i.e. domain, protocol, port match document) */
  3037 src: url(fonts/simple.ttf);
  3038 src: url(//fonts/simple.ttf);
  3040 /* cross origin, different protocol */
  3041 src: url(https://example.com/fonts/simple.ttf);
  3043 /* cross origin, different domain */
  3044 src: url(http://another.example.com/fonts/simple.ttf);
  3045 </pre>
  3047   <h4 id=allowing-cross-origin-font-loading><span class=secno>4.9.2
  3048    </span>Allowing cross-origin font loading</h4>
  3050   <p>User agents must also implement the ability to relax this restriction
  3051    using cross-site origin controls <a href="#CORS"
  3052    rel=biblioentry>[CORS]<!--{{!CORS}}--></a> for fonts loaded via HTTP.
  3053    Sites can explicitly allow cross-site downloading of font data using the
  3054    <code>Access-Control-Allow-Origin</code> HTTP header. For other protocols,
  3055    no explicit relaxation mechanism is defined or required.
  3057   <p>For font loads over HTTP, cross-origin requests must be made with the
  3058    following parameter settings which are used in conjunction with the <a
  3059    href="http://www.w3.org/TR/cors/#cross-origin-request-0"> <em>cross-origin
  3060    request algorithm</em></a> <a href="#CORS"
  3061    rel=biblioentry>[CORS]<!--{{!CORS}}--></a>:
  3063   <ul>
  3064    <li><em>request URL</em> — the URL of the font resource in the <a
  3065     href="#descdef-src"><code>src</code></a> descriptor
  3067    <li><em>request method</em> — GET
  3069    <li><em>author request headers</em> — none
  3071    <li><em>request entity body</em> — empty
  3073    <li><em>source origin</em> — the origin of the page which linked to the
  3074     stylesheet
  3076    <li><em>manual redirect flag</em> — false
  3078    <li><em>omit credentials flag</em> — true
  3080    <li><em>force preflight flag</em> — false
  3081   </ul>
  3083   <h2 id=font-matching-algorithm><span class=secno>5 </span>Font Matching
  3084    Algorithm</h2>
  3086   <p>The algorithm below describes how fonts are associated with individual
  3087    runs of text. For each character in the run a font family is chosen and a
  3088    particular font face is selected containing a glyph for that character.
  3090   <h3 id=font-family-casing><span class=secno>5.1 </span>Case sensitivity of
  3091    font family names</h3>
  3093   <p>As part of the font matching algorithm outlined below, user agents must
  3094    match font family names used in style rules with actual font family names
  3095    contained in fonts available in a given environment or defined via <a
  3096    href="#at-font-face-rule"><code>@font-face</code></a> rules. User agents
  3097    must match these names case insensitively, using the "Default Caseless
  3098    Matching" algorithm outlined in the Unicode specification <a
  3099    href="#UNICODE6" rel=biblioentry>[UNICODE6]<!--{{!UNICODE6}}--></a>. This
  3100    algorithm is detailed in section 3.13 entitled "Default Case Algorithms".
  3101    Specifically, the algorithm must be applied without normalizing the
  3102    strings involved and without applying any language-specific tailorings.
  3103    The case folding method specified by this algorithm uses the case mappings
  3104    with status field ‘<code class=property>C</code>’ or ‘<code
  3105    class=property>F</code>’ in the CaseFolding.txt file of the Unicode
  3106    Character Database.
  3108   <p class=note> Implementors should take care to verify that a given
  3109    caseless string comparison implementation uses this precise algorithm and
  3110    not assume that a given platform string matching routine follows it, as
  3111    many of these have locale-specific behavior or use some level of string
  3112    normalization.
  3114   <p class=note> For authors this means that font family names are matched
  3115    case insensitively, whether those names exist in a platform font or in the
  3116    <a href="#at-font-face-rule"><code>@font-face</code></a> rules contained
  3117    in a stylesheet. Authors should take care to ensure that names use a
  3118    character sequence consistent with the actual font family name,
  3119    particularly when using combining characters such as diacritical marks.
  3120    For example, a family name that contains an uppercase A (U+0041) followed
  3121    by a combining ring (U+030A) will <strong>not</strong> match a name that
  3122    looks identical but which uses the precomposed lowercase a-ring character
  3123    (U+00E5) instead of the combining sequence.
  3125   <h3 id=font-style-matching><span class=secno>5.2 </span>Matching font
  3126    styles</h3>
  3128   <p>The procedure for choosing fonts consists of iterating over the font
  3129    families determined by the font-family property, selecting a font face
  3130    with the appropriate style based on other font properties and then
  3131    determining whether a glyph exists for a given character. This is done
  3132    using the <dfn id=character-map>character map</dfn> of the font, data
  3133    which maps characters to the default glyph for that character. Codepoint
  3134    sequences consisting of a base character followed by a sequence of
  3135    combining characters are treated slightly differently, see the section on
  3136    <a href="#cluster-matching">cluster matching</a> below.
  3138   <p>For this procedure, the <dfn id=default-face>default face</dfn> for a
  3139    given font family is defined to be the face that would be selected if all
  3140    font style properties were set to their initial value.
  3142   <ol id=fontmatchingalg>
  3143    <li>Using the computed font property values for a given element, the user
  3144     agent starts with the first family name in the fontlist specified by the
  3145     <a href="#propdef-font-family" title="font-family!!property">‘<code
  3146     class=property>font-family</code>’</a> property.
  3148    <li>If the family name is unquoted and is a generic family name, the user
  3149     agent looks up the appropriate font family name to be used. User agents
  3150     may choose the generic font family to use based on the language of the
  3151     containing element or the Unicode range of the character.
  3153    <li>For other family names, the user agent attempts to find the family
  3154     name among fonts defined via <a
  3155     href="#at-font-face-rule"><code>@font-face</code></a> rules and then
  3156     among available system fonts, matching names with a case-insensitive
  3157     comparison as outlined <a href="#font-family-casing">in the section
  3158     above</a>. On systems containing fonts with multiple localized font
  3159     family names, user agents must match any of these names independent of
  3160     the underlying system locale or platform API used. If the font resources
  3161     defined for a given face in an <a
  3162     href="#at-font-face-rule"><code>@font-face</code></a> rule are either not
  3163     available or contain invalid font data, then the face should be treated
  3164     as not present in the family. If no faces are present for a family
  3165     defined via <a href="#at-font-face-rule"><code>@font-face</code></a>
  3166     rules, the family should be treated as missing; matching a platform font
  3167     with the same name must not occur in this case.
  3169    <li>If a font family match occurs, the user agent assembles the set of
  3170     font faces in that family and then narrows the set to a single face using
  3171     other font properties in the order given below:
  3172     <ol id=fontstylematchingalg>
  3173      <li><a href="#propdef-font-stretch"
  3174       title="font-stretch!!property">‘<code
  3175       class=property>font-stretch</code>’</a> is tried first. If the
  3176       matching set contains faces with width values matching the <a
  3177       href="#propdef-font-stretch" title="font-stretch!!property">‘<code
  3178       class=property>font-stretch</code>’</a> value, faces with other width
  3179       values are removed from the matching set. If there is no face that
  3180       exactly matches the width value the nearest width is used instead. If
  3181       the value of <a href="#propdef-font-stretch"
  3182       title="font-stretch!!property">‘<code
  3183       class=property>font-stretch</code>’</a> is <a
  3184       href="#font-stretch-normal-value" title="normal!!font-stretch">‘<code
  3185       class=property>normal</code>’</a> or one of the condensed values,
  3186       narrower width values are checked first, then wider values. If the
  3187       value of <a href="#propdef-font-stretch"
  3188       title="font-stretch!!property">‘<code
  3189       class=property>font-stretch</code>’</a> is one of the expanded
  3190       values, wider values are checked first, followed by narrower values.
  3191       Once the closest matching width has been determined by this process,
  3192       faces with other widths are removed from the matching set.
  3194      <li><a href="#propdef-font-style" title="font-style!!property">‘<code
  3195       class=property>font-style</code>’</a> is tried next. If the value of
  3196       <a href="#propdef-font-style" title="font-style!!property">‘<code
  3197       class=property>font-style</code>’</a> is ‘<a href="#italic"><code
  3198       class=property>italic</code></a>’, italic faces are checked first,
  3199       then oblique, then normal faces. If the value is ‘<a
  3200       href="#oblique"><code class=property>oblique</code></a>’, oblique
  3201       faces are checked first, then italic faces and then normal faces. If
  3202       the value is <a href="#font-style-normal-value"
  3203       title="normal!!font-style">‘<code
  3204       class=property>normal</code>’</a>, normal faces are checked first,
  3205       then oblique faces, then italic faces. Faces with other style values
  3206       are excluded from the matching set. User agents are permitted to
  3207       distinguish between italic and oblique faces within platform font
  3208       families but this is not required, they may treat all italic or oblique
  3209       faces as italic faces. However, within font families defined via <a
  3210       href="#at-font-face-rule"><code>@font-face</code></a> rules, italic and
  3211       oblique faces must be distinguished using the value of the <a
  3212       href="#descdef-font-style" title="font-style!!descriptor">‘<code
  3213       class=property>font-style</code>’</a> descriptor.
  3215      <li><a href="#propdef-font-weight"
  3216       title="font-weight!!property">‘<code
  3217       class=property>font-weight</code>’</a> is matched next, it will
  3218       always reduce the matching set to a single font face. If bolder/lighter
  3219       relative weights are used, the effective weight is calculated based on
  3220       the inherited weight value, as described in the definition of the <a
  3221       href="#propdef-font-weight" title="font-weight!!property">‘<code
  3222       class=property>font-weight</code>’</a> property. Given the desired
  3223       weight and the weights of faces in the matching set after the steps
  3224       above, if the desired weight is available that face matches. Otherwise,
  3225       a weight is chosen using the rules below:
  3226       <ul>
  3227        <li>If the desired weight is less than 400, weights below the desired
  3228         weight are checked in descending order followed by weights above the
  3229         desired weight in ascending order until a match is found.
  3231        <li>If the desired weight is greater than 500, weights above the
  3232         desired weight are checked in ascending order followed by weights
  3233         below the desired weight in descending order until a match is found.
  3235        <li>If the desired weight is 400, 500 is checked first and then the
  3236         rule for desired weights less than 400 is used.
  3238        <li>If the desired weight is 500, 400 is checked first and then the
  3239         rule for desired weights less than 400 is used.
  3240       </ul>
  3242      <li><span class=property>‘<a href="#propdef-font-size"><code
  3243       class=property>font-size</code></a>’</span> must be matched within a
  3244       UA-dependent margin of tolerance. (Typically, sizes for scalable fonts
  3245       are rounded to the nearest whole pixel, while the tolerance for
  3246       bitmapped fonts could be as large as 20%.) Further computations, e.g.,
  3247       by ‘<code class=property>em</code>’ values in other properties, are
  3248       based on the <span class=property>‘<a href="#propdef-font-size"><code
  3249       class=property>font-size</code></a>’</span> value that is used, not
  3250       the one that is specified.
  3251     </ol>
  3253    <li>
  3254     <p>If no matching face exists or the matched face does not contain a
  3255      glyph for the character to be rendered, the next family name is selected
  3256      and the previous two steps repeated. Glyphs from other faces in the
  3257      family are not considered. The only exception is that user agents may
  3258      optionally substitute a synthetic version of the <a
  3259      href="#default-face"><em>default face</em></a> if that face supports a
  3260      given glyph (e.g. a synthetic italic version of the regular face may be
  3261      used if the italic face doesn't support glyphs for Arabic).</p>
  3262     <!-- resolution on the above: http://lists.w3.org/Archives/Public/www-style/2012Nov/0292.html -->
  3264     <p>If the matched font is defined via an <a
  3265      href="#at-font-face-rule"><code>@font-face</code></a> rule and needs to
  3266      be downloaded, the font resource is downloaded. While the download
  3267      occurs, the user agent can either wait until the font is downloaded or
  3268      render once with substituted font metrics and render again once the font
  3269      is downloaded.</p>
  3271    <li>If there are no more font families to be evaluated and no matching
  3272     face has been found, then the user agent performs a <dfn
  3273     id=system-font-fallback>system font fallback</dfn> procedure to find the
  3274     best match for the character to be rendered. The result of this procedure
  3275     may vary across user agents.
  3277    <li>If a particular character cannot be displayed using any font, the user
  3278     agent should indicate by some means that a character is not being
  3279     displayed, displaying either a symbolic representation of the missing
  3280     glyph (e.g. using a <a
  3281     href="http://en.wikipedia.org/wiki/Last_resort_font">Last Resort
  3282     Font</a>) or using the missing character glyph from a default font.
  3283   </ol>
  3285   <h3 id=cluster-matching><span class=secno>5.3 </span>Cluster matching</h3>
  3287   <p>When text contains characters such as combining diacritics, ideally the
  3288    base character should be rendered using the same font as the diacritic,
  3289    this assures proper placement of the diacritic. For this reason, the font
  3290    matching algorithm for clusters is more specialized than the general case
  3291    of matching a single character by itself. For sequences containing
  3292    variation selectors, which indicate the precise glyph to be used for a
  3293    given character, user agents always attempt <a
  3294    href="#system-font-fallback"><em>system font fallback</em></a> to find the
  3295    appropriate glyph before using the default glyph of the base character.
  3297   <p>A font is considered to <em>support</em> a given character if (1) the
  3298    character is contained in the font's <a
  3299    href="#character-map"><em>character map</em></a> and (2) if required by
  3300    the containing script, shaping information is available for that
  3301    character. Some legacy fonts may include a given character in the <a
  3302    href="#character-map"><em>character map</em></a> but lack the shaping
  3303    information (e.g. <a
  3304    href="http://www.microsoft.com/typography/otspec/ttochap1.htm">OpenType
  3305    layout tables</a> or <a
  3306    href="http://scripts.sil.org/cms/scripts/page.php?site_id=projects&amp;item_id=graphite_techAbout">Graphite
  3307    tables</a>) necessary for correctly rendering text runs containing that
  3308    character.
  3310   <p>A sequence of codepoints containing combining diacritics or other
  3311    modifiers is termed a grapheme cluster (see <a href="#CSS3TEXT"
  3312    rel=biblioentry>[CSS3TEXT]<!--{{CSS3TEXT}}--></a> for a more complete
  3313    description). For a given cluster containing a base character, <em>b</em>
  3314    and a sequence of combining characters <em>c1, c2…</em>, the entire
  3315    cluster is matched using these steps:
  3317   <ol>
  3318    <li>For each family in the font list, a face is chosen using the style
  3319     selection rules defined in the previous section.
  3320     <ol>
  3321      <li>If all characters in the sequence <em>b + c1 + c2 …</em> are
  3322       completely supported by the font, select this font for the sequence.
  3324      <li>If a sequence of multiple codepoints is canonically equivalent to a
  3325       single character and the font supports that character, select this font
  3326       for the sequence.
  3327     </ol>
  3329    <li>If no font was found in the font list in step 1:
  3330     <ol>
  3331      <li>If <em>c1</em> is a variation selector, system fallback must be used
  3332       to find a font that supports the full sequence of <em>b + c1</em>. If
  3333       no font on the system supports the full sequence, match the single
  3334       character <em>b</em> using the normal procedure for matching single
  3335       characters and ignore the variation selector. Note: a sequence with
  3336       more than one variation selector is treated as an encoding error and
  3337       the trailing selectors are ignored.
  3339      <li>Otherwise, the user agent may optionally use system font fallback to
  3340       match a font that supports the entire cluster.
  3341     </ol>
  3343    <li>If no font is found in step 2, use the matching sequence from step 1
  3344     to determine the longest sequence that is completely matched by a font in
  3345     the font list and attempt to match the remaining combining characters
  3346     separately using the rules for single characters.
  3347   </ol>
  3349   <h3 id=char-handling-issues><span class=secno>5.4 </span>Character handling
  3350    issues</h3>
  3352   <p>The procedure above is always performed on text runs containing Unicode
  3353    characters, documents using legacy encodings are assumed to have been
  3354    transcoded before matching fonts. For fonts containing <a
  3355    href="#character-map"><em title="character map">character maps</em></a>
  3356    for both legacy encodings and Unicode, the contents of the legacy encoding
  3357    <a href="#character-map"><em>character map</em></a> must have no effect on
  3358    the results of the font matching process.
  3360   <p>The font matching process does not assume that text runs are in either
  3361    normalized or denormalized form (see <a href="#CHARMOD-NORM"
  3362    rel=biblioentry>[CHARMOD-NORM]<!--{{CHARMOD-NORM}}--></a> for more
  3363    details). Layout engines often convert base character plus combining
  3364    character sequences into precomposed characters if they exist. The font
  3365    matching algorithm outlined here supports both ways and fonts can
  3366    generally support either but variations can occur. Authors should always
  3367    tailor their choice of fonts to their content, including whether that
  3368    content contains normalized or denormalized character streams.
  3370   <p>If a given character is a Private-Use Area Unicode codepoint and none of
  3371    the fonts in the fontlist contain a glyph for that codepoint, user agents
  3372    must display some form of missing glyph symbol for that character rather
  3373    than attempting <a href="#system-font-fallback"><em>system font
  3374    fallback</em></a> for that codepoint. When matching the replacement
  3375    character U+FFFD, user agents may skip the font matching process and
  3376    immediately display some form of missing glyph symbol, they are not
  3377    required to display the glyph from the font that would be selected by the
  3378    font matching process.
  3380   <p>In general, the fonts for a given family will all have the same or
  3381    similar <a href="#character-map"><em title="character map">character
  3382    maps</em></a>. The process outlined here is designed to handle even font
  3383    families containing faces with widely variant <a href="#character-map"><em
  3384    title="character map">character maps</em></a>. However, authors are
  3385    cautioned that the use of such families can lead to unexpected results.
  3387   <p>Optimizations of this process are allowed provided that an
  3388    implementation behaves as if the algorithm had been followed exactly.
  3389    Matching occurs in a well-defined order to insure that the results are as
  3390    consistent as possible across user agents, given an identical set of
  3391    available fonts and rendering technology.
  3393   <h3 id=font-matching-changes><span class=secno>5.5 </span>Font matching
  3394    changes since CSS 2.1</h3>
  3396   <p>The algorithm above is different from CSS 2.1 in a number of key places.
  3397    These changes were made to better reflect actual font matching behavior
  3398    across user agent implementations.
  3400   <p>Differences compared to the font matching algorithm in CSS 2.1:
  3402   <ul>
  3403    <li>The algorithm includes font-stretch matching.
  3405    <li>All possible font-style matching scenarios are delineated.
  3407    <li>Small-caps fonts are not matched as part of the font matching process,
  3408     they are now handled via font features.
  3410    <li>Unicode variation selector matching is required.
  3412    <li>Cluster sequences are matched as a unit.
  3413   </ul>
  3415   <h3 id=font-matching-examples><span class=secno>5.6 </span>Font matching
  3416    examples</h3>
  3418   <div class=example>
  3419    <p>It's useful to note that the CSS selector syntax may be used to create
  3420     language-sensitive typography. For example, some Chinese and Japanese
  3421     characters are unified to have the same Unicode code point, although the
  3422     abstract glyphs are not the same in the two languages.
  3424    <pre>*:lang(ja-jp) { font: 900 14pt/16pt &quot;Heisei Mincho W9&quot;, serif; }
  3425 *:lang(zh-tw) { font: 800 14pt/16.5pt &quot;Li Sung&quot;, serif; }
  3426 </pre>
  3428    <p>This selects any element that has the given language - Japanese or
  3429     Traditional Chinese - and uses the appropriate font.
  3430   </div>
  3432   <h2 id=font-rend-props><span class=secno>6 </span>Font Feature Properties</h2>
  3434   <p>Modern font technologies support a variety of advanced typographic and
  3435    language-specific font features. Using these features, a single font can
  3436    provide glyphs for a wide range of ligatures, contextual and stylistic
  3437    alternates, tabular and old-style figures, small capitals, automatic
  3438    fractions, swashes, and alternates specific to a given language. To allow
  3439    authors control over these font capabilities, the ‘<code
  3440    class=property>font-variant</code>’ property has been expanded for CSS3.
  3441    It now functions as a shorthand for a set of properties that provide
  3442    control over stylistic font features.
  3444   <h3 id=glyph-selection-positioning><span class=secno>6.1 </span>Glyph
  3445    selection and positioning</h3>
  3447   <p>Simple fonts used for displaying Latin text use a very basic processing
  3448    model. Fonts contain a <a href="#character-map"><em>character map</em></a>
  3449    which maps each character to a glyph for that character. Glyphs for
  3450    subsequent characters are simply placed one after the other along a run of
  3451    text. Modern font formats such as OpenType and AAT (Apple Advanced
  3452    Typography) use a richer processing model. The glyph for a given character
  3453    can be chosen and positioned not just based on the codepoint of the
  3454    character itself, but also on adjacent characters as well as the language,
  3455    script, and features enabled for the text. Font features may be required
  3456    for specific scripts, or recommended as enabled by default or they might
  3457    be stylistic features meant to be used under author control.
  3459   <p>For a good visual overview of these features, see the <a
  3460    href="#OPENTYPE-FONT-GUIDE"
  3461    rel=biblioentry>[OPENTYPE-FONT-GUIDE]<!--{{OPENTYPE-FONT-GUIDE}}--></a>.
  3462    For a detailed description of glyph processing for OpenType fonts, see <a
  3463    href="#WINDOWS-GLYPH-PROC"
  3464    rel=biblioentry>[WINDOWS-GLYPH-PROC]<!--{{WINDOWS-GLYPH-PROC}}--></a>.
  3466   <p>Stylistic font features can be classified into two broad categories:
  3467    ones that affect the harmonization of glyph shapes with the surrounding
  3468    context, such as kerning and ligature features, and ones such as the
  3469    small-caps, subscript/superscript and alternate features that affect shape
  3470    selection.
  3472   <p>The subproperties of <a href="#propdef-font-variant"
  3473    title="font-variant!!property">‘<code
  3474    class=property>font-variant</code>’</a> listed below are used to control
  3475    these stylistic font features. They do not control features that are
  3476    required for displaying certain scripts, such as the OpenType features
  3477    used when displaying Arabic or Indic language text. They affect glyph
  3478    selection and positioning, but do not affect font selection as described
  3479    in the font matching section (except in cases required for compatibility
  3480    with CSS 2.1).
  3482   <p>To assure consistent behavior across user agents, the equivalent
  3483    OpenType property settings are listed for individual properties and are
  3484    normative. When using other font formats these should be used as a
  3485    guideline to map CSS font feature property values to specific font
  3486    features.
  3488   <h3 id=language-specific-support><span class=secno>6.2
  3489    </span>Language-specific display</h3>
  3491   <p>OpenType also supports language-specific glyph selection and
  3492    positioning, so that text can be displayed correctly in cases where the
  3493    language dictates a specific display behavior. Many languages share a
  3494    common script, but the shape of certain letters can vary across those
  3495    languages. For example, certain Cyrillic letters have different shapes in
  3496    Russian text than in Bulgarian. In Latin text, it's common to render "fi"
  3497    with an explicit fi-ligature that lacks a dot on the "i". However, in
  3498    languages such as Turkish which uses both a dotted-i and a dotless-i, it's
  3499    important to not use this ligature or use a specialized version that
  3500    contains a dot over the "i". The example below shows language-specific
  3501    variations based on stylistic traditions found in Spanish, Italian and
  3502    French orthography:
  3504   <div class=featex><img alt="language specific forms, spanish"
  3505    src=locl-1.png></div>
  3507   <div class=featex><img alt="language specific forms, italian"
  3508    src=locl-2.png></div>
  3510   <div class=featex><img alt="language specific forms, french"
  3511    src=locl-3.png></div>
  3513   <p>If the content language of the element is known according to the rules
  3514    of the <a
  3515    href="http://www.w3.org/TR/CSS21/conform.html#doclanguage">document
  3516    language</a>, user agents are required to infer the OpenType language
  3517    system from the content language and use that when selecting and
  3518    positioning glyphs using an OpenType font.
  3520   <p>For OpenType fonts, in some cases it may be necessary to explicitly
  3521    declare the OpenType language to be used, for example when displaying text
  3522    in a given language that uses the typographic conventions of another
  3523    language or when the font does not explicitly support a given language but
  3524    supports a language that shares common typographic conventions. The ‘<a
  3525    href="#propdef-font-language-override"><code
  3526    class=property>font-language-override</code></a>’ property is used for
  3527    this purpose.</p>
  3528   <!-- prop: font-kerning -->
  3530   <h3 id=font-kerning-prop><span class=secno>6.3 </span>Kerning: the <a
  3531    href="#propdef-font-kerning">font-kerning</a> property</h3>
  3533   <table class=propdef id=namefont-kerningvalueauto-normal-noneini>
  3534    <tbody>
  3535     <tr>
  3536      <td>Name:
  3538      <td><dfn id=propdef-font-kerning>font-kerning</dfn>
  3540     <tr>
  3541      <td>Value:
  3543      <td><a href="#font-kerning-auto-value"
  3544       title="auto!!font-kerning">auto</a> | <a
  3545       href="#font-kerning-normal-value"
  3546       title="normal!!font-kerning">normal</a> | <a
  3547       href="#font-kerning-none-value" title="none!!font-kerning">none</a>
  3549     <tr>
  3550      <td>Initial:
  3552      <td>auto
  3554     <tr>
  3555      <td>Applies to:
  3557      <td>all elements
  3559     <tr>
  3560      <td>Inherited:
  3562      <td>yes
  3564     <tr>
  3565      <td>Percentages:
  3567      <td>N/A
  3569     <tr>
  3570      <td>Media:
  3572      <td>visual
  3574     <tr>
  3575      <td>Computed value:
  3577      <td>as specified
  3579     <tr>
  3580      <td>Animatable:
  3582      <td>no
  3583   </table>
  3585   <p>Kerning is the contextual adjustment of inter-glyph spacing. This
  3586    property controls metric kerning, kerning that utilizes adjustment data
  3587    contained in the font.
  3589   <dl>
  3590    <dt><dfn id=font-kerning-auto-value title="auto!!font-kerning">auto</dfn>
  3592    <dd>Specifies that kerning is applied at the discretion of the user agent
  3594    <dt><dfn id=font-kerning-normal-value
  3595     title="normal!!font-kerning">normal</dfn>
  3597    <dd>Specifies that kerning is applied
  3599    <dt><dfn id=font-kerning-none-value title="none!!font-kerning">none</dfn>
  3601    <dd>Specifies that kerning is not applied
  3602   </dl>
  3604   <p>For fonts that do not include kerning data this property will have no
  3605    visible effect. When rendering with OpenType fonts, the <a
  3606    href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>
  3607    specification suggests that kerning be enabled by default. When kerning is
  3608    enabled, the OpenType <span class=tag>kern</span> feature is enabled (for
  3609    vertical text runs the <span class=tag>vkrn</span> feature is enabled
  3610    instead). User agents must also support fonts that only support kerning
  3611    via data contained in a <span class=tag>kern</span> font table, as
  3612    detailed in the OpenType specification. If the ‘<code
  3613    class=property>letter-spacing</code>’ property is defined, kerning
  3614    adjustments are considered part of the default spacing and letter spacing
  3615    adjustments are made after kerning has been applied.
  3617   <p>When set to ‘<code class=property>auto</code>’, user agents can
  3618    determine whether to apply kerning or not based on a number of factors:
  3619    text size, script, or other factors that influence text processing speed.
  3620    Authors who want proper kerning should use <a
  3621    href="#font-kerning-normal-value" title="normal!!font-kerning">‘<code
  3622    class=property>normal</code>’</a> to explicitly enable kerning.
  3623    Likewise, some authors may prefer to disable kerning in situations where
  3624    performance is more important than precise appearance. However, in
  3625    well-designed modern implementations the use of kerning generally does not
  3626    have a large impact on text rendering speed.</p>
  3627   <!-- prop: font-variant-ligatures -->
  3629   <h3 id=font-variant-ligatures-prop><span class=secno>6.4 </span>Ligatures:
  3630    the <a href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
  3631    property</h3>
  3633   <table class=propdef id=namefont-variant-ligaturesvaluenormal-no>
  3634    <tbody>
  3635     <tr>
  3636      <td>Name:
  3638      <td><dfn id=propdef-font-variant-ligatures>font-variant-ligatures</dfn>
  3640     <tr>
  3641      <td>Value:
  3643      <td><a href="#font-variant-ligatures-normal-value"
  3644       title="normal!!font-variant-ligatures">normal</a> | <a
  3645       href="#font-variant-ligatures-none-value"
  3646       title="none!!font-variant-ligatures">none</a> | [ <a
  3647       href="#common-lig-values"><var>&lt;common-lig-values&gt;</var></a> ||
  3648       <a
  3649       href="#discretionary-lig-values"><var>&lt;discretionary-lig-values&gt;</var></a>
  3650       || <a
  3651       href="#historical-lig-values"><var>&lt;historical-lig-values&gt;</var></a>
  3652       || <a
  3653       href="#contextual-alt-values"><var>&lt;contextual-alt-values&gt;</var></a>
  3656     <tr>
  3657      <td>Initial:
  3659      <td>normal
  3661     <tr>
  3662      <td>Applies to:
  3664      <td>all elements
  3666     <tr>
  3667      <td>Inherited:
  3669      <td>yes
  3671     <tr>
  3672      <td>Percentages:
  3674      <td>N/A
  3676     <tr>
  3677      <td>Media:
  3679      <td>visual
  3681     <tr>
  3682      <td>Computed value:
  3684      <td>as specified
  3686     <tr>
  3687      <td>Animatable:
  3689      <td>no
  3690   </table>
  3692   <p>Ligatures and contextual forms are ways of combining glyphs to produce
  3693    more harmonized forms.
  3695   <pre
  3696    class=prod><dfn id=common-lig-values><var>&lt;common-lig-values&gt;</var></dfn>        = [ <a href="#common-ligatures">common-ligatures</a> | <a href="#no-common-ligatures">no-common-ligatures</a> ]</pre>
  3698   <pre
  3699    class=prod><dfn id=discretionary-lig-values><var>&lt;discretionary-lig-values&gt;</var></dfn> = [ <a href="#discretionary-ligatures">discretionary-ligatures</a> | <a href="#no-discretionary-ligatures">no-discretionary-ligatures</a> ]</pre>
  3701   <pre
  3702    class=prod><dfn id=historical-lig-values><var>&lt;historical-lig-values&gt;</var></dfn>    = [ <a href="#historical-ligatures">historical-ligatures</a> | <a href="#no-historical-ligatures">no-historical-ligatures</a> ]</pre>
  3704   <pre
  3705    class=prod><dfn id=contextual-alt-values><var>&lt;contextual-alt-values&gt;</var></dfn>    = [ <a href="#contextual">contextual</a> | <a href="#no-contextual">no-contextual</a> ]</pre>
  3707   <p>Individual values have the following meanings:
  3709   <dl>
  3710    <dt><dfn id=font-variant-ligatures-normal-value
  3711     title="normal!!font-variant-ligatures">normal</dfn>
  3713    <dd>A value of <a href="#font-variant-ligatures-normal-value"
  3714     title="normal!!font-variant-ligatures">‘<code
  3715     class=property>normal</code>’</a> specifies that common default
  3716     features are enabled, <a href="#font-feature-resolution">as described in
  3717     detail in the next section</a>. For OpenType fonts, common ligatures and
  3718     contextual forms are on by default, discretionary and historical
  3719     ligatures are not.
  3721    <dt><dfn id=font-variant-ligatures-none-value
  3722     title="none!!font-variant-ligatures">none</dfn>
  3724    <dd>Specifies that all types of ligatures and contextual forms covered by
  3725     this property are explicitly disabled. In situations where ligatures are
  3726     not considered necessary, this may improve the speed of text rendering.
  3728    <dt><dfn id=common-ligatures>common-ligatures</dfn>
  3730    <dd>Enables display of common ligatures (OpenType features: <span
  3731     class=tag>liga, clig</span>). For OpenType fonts, common ligatures are
  3732     enabled by default.
  3733   </dl>
  3735   <div class=featex><img alt="common ligature example" src=liga.png></div>
  3737   <dl>
  3738    <dt><dfn id=no-common-ligatures>no-common-ligatures</dfn>
  3740    <dd>Disables display of common ligatures (OpenType features: <span
  3741     class=tag>liga, clig</span>).
  3743    <dt><dfn id=discretionary-ligatures>discretionary-ligatures</dfn>
  3745    <dd>Enables display of discretionary ligatures (OpenType feature: <span
  3746     class=tag>dlig</span>). Which ligatures are discretionary or optional is
  3747     decided by the type designer, so authors will need to refer to the
  3748     documentation of a given font to understand which ligatures are
  3749     considered discretionary.
  3750   </dl>
  3752   <div class=featex><img alt="discretionary ligature example" src=dlig.png></div>
  3754   <dl>
  3755    <dt><dfn id=no-discretionary-ligatures>no-discretionary-ligatures</dfn>
  3757    <dd>Disables display of discretionary ligatures (OpenType feature: <span
  3758     class=tag>dlig</span>).
  3760    <dt><dfn id=historical-ligatures>historical-ligatures</dfn>
  3762    <dd>Enables display of historical ligatures (OpenType feature: <span
  3763     class=tag>hlig</span>).
  3764   </dl>
  3766   <div class=featex><img alt="historical ligature example" src=hlig.png></div>
  3768   <dl>
  3769    <dt><dfn id=no-historical-ligatures>no-historical-ligatures</dfn>
  3771    <dd>Disables display of historical ligatures (OpenType feature: <span
  3772     class=tag>hlig</span>).
  3774    <dt><dfn id=contextual>contextual</dfn>
  3776    <dd>Enables display of contextual alternates (OpenType feature: <span
  3777     class=tag>calt</span>). Although not strictly a ligature feature, like
  3778     ligatures this feature is commonly used to harmonize the shapes of glyphs
  3779     with the surrounding context. For OpenType fonts, this feature is on by
  3780     default.
  3781   </dl>
  3783   <div class=featex><img alt="contextual alternate example" src=calt.png></div>
  3785   <dl>
  3786    <dt><dfn id=no-contextual>no-contextual</dfn>
  3788    <dd>Disables display of contextual alternates (OpenType feature: <span
  3789     class=tag>calt</span>).
  3790   </dl>
  3792   <p>Required ligatures, needed for correctly rendering complex scripts, are
  3793    not affected by the settings above, including ‘<code
  3794    class=property>none</code>’ (OpenType feature: <span
  3795    class=tag>rlig</span>).</p>
  3796   <!-- prop: font-variant-position -->
  3798   <h3 id=font-variant-position-prop><span class=secno>6.5 </span>Subscript
  3799    and superscript forms: the <a
  3800    href="#propdef-font-variant-position">font-variant-position</a> property</h3>
  3802   <table class=propdef id=namefont-variant-positionvaluenormal-sub>
  3803    <tbody>
  3804     <tr>
  3805      <td>Name:
  3807      <td><dfn id=propdef-font-variant-position>font-variant-position</dfn>
  3809     <tr>
  3810      <td>Value:
  3812      <td><a href="#font-variant-position-normal-value"
  3813       title="normal!!font-variant-position">normal</a> | <a
  3814       href="#sub">sub</a> | <a href="#super">super</a>
  3816     <tr>
  3817      <td>Initial:
  3819      <td>normal
  3821     <tr>
  3822      <td>Applies to:
  3824      <td>all elements
  3826     <tr>
  3827      <td>Inherited:
  3829      <td>yes
  3831     <tr>
  3832      <td>Percentages:
  3834      <td>N/A
  3836     <tr>
  3837      <td>Media:
  3839      <td>visual
  3841     <tr>
  3842      <td>Computed value:
  3844      <td>as specified
  3846     <tr>
  3847      <td>Animatable:
  3849      <td>no
  3850   </table>
  3852   <p>This property is used to enable typographic subscript and superscript
  3853    glyphs. These are alternate glyphs designed within the same em-box as
  3854    default glyphs and are intended to be laid out on the same baseline as the
  3855    default glyphs, with no resizing or repositioning of the baseline. They
  3856    are explicitly designed to match the surrounding text and to be more
  3857    readable without affecting the line height.
  3859   <div class=figure><img alt="comparison between real subscript glyphs and
  3860    synthesized ones" src=realsubscripts.png>
  3861    <p class=caption>Subscript glyphs (top) vs. typical synthesized subscripts
  3862     (bottom)
  3863   </div>
  3865   <p>Individual values have the following meanings:
  3867   <dl>
  3868    <dt><dfn id=font-variant-position-normal-value
  3869     title="normal!!font-variant-position">normal</dfn>
  3871    <dd>None of the features listed below are enabled.
  3873    <dt><dfn id=sub>sub</dfn>
  3875    <dd>Enables display of subscript variants (OpenType feature: <span
  3876     class=tag>subs</span>).
  3878    <dt><dfn id=super>super</dfn>
  3880    <dd>Enables display of superscript variants (OpenType feature: <span
  3881     class=tag>sups</span>).
  3882   </dl>
  3884   <p>Because of the semantic nature of subscripts and superscripts, when the
  3885    value is either ‘<a href="#sub"><code class=property>sub</code></a>’
  3886    or ‘<a href="#super"><code class=property>super</code></a>’ for a
  3887    given contiguous run of text, if a variant glyph is not available for all
  3888    the characters in the run, simulated glyphs must be synthesized for all
  3889    characters using reduced forms of the glyphs that would be used without
  3890    this feature applied. This is done per run to avoid a mixture of variant
  3891    glyphs and synthesized ones that would not align correctly. In the case of
  3892    OpenType fonts that lack subscript or superscript glyphs for a given
  3893    character, user agents must use the appropriate subscript and superscript
  3894    metrics specified in the selected font's <a
  3895    href="http://www.microsoft.com/typography/otspec/os2.htm#subxs">OS/2
  3896    table</a> <a href="#OPENTYPE"
  3897    rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> to calculate the size
  3898    and offset of the synthesized substitutes.
  3900   <div class=figure><img alt="alternate superscripts vs. glyphs synthesized
  3901    using superscript metrics" src=superscript-alt-synth.png>
  3902    <p class=caption>Superscript alternate glyph (left), synthesized
  3903     superscript glyphs (middle), and incorrect mixture of the two (right)
  3904   </div>
  3906   <p>In the past, user agents have used font-size and vertical-align to
  3907    simulate subscripts and superscripts for the <code title="HTML sub
  3908    element">sub</code> and <code title="HTML sup element">sup</code>
  3909    elements. To allow a backwards compatible way of defining subscripts and
  3910    superscripts, it is recommended that authors use conditional rules <a
  3911    href="#CSS3-CONDITIONAL"
  3912    rel=biblioentry>[CSS3-CONDITIONAL]<!--{{CSS3-CONDITIONAL}}--></a> so that
  3913    older user agents will still render subscripts and superscripts via the
  3914    older mechanism.
  3916   <p>Authors should note that fonts typically only provide subscript and
  3917    superscript glyphs for a subset of all characters supported by the font.
  3918    For example, while subscript and superscript glyphs are often available
  3919    for Latin numbers, glyphs for punctuation and letter characters are less
  3920    frequently provided. The synthetic fallback rules defined for this
  3921    property assure that subscripts and superscripts will always appear but
  3922    the appearance may not match author expectations if the font used does not
  3923    provide the appropriate alternate glyph for all characters contained in a
  3924    subscript or superscript.
  3926   <p>This property is not cumulative. Applying it to elements within a
  3927    subscript or superscript won't nest the placement of a subscript or
  3928    superscript glyph. Images contained within text runs where the value of
  3929    this property is ‘<a href="#sub"><code class=property>sub</code></a>’
  3930    or ‘<a href="#super"><code class=property>super</code></a>’ will be
  3931    drawn just as they would if the value was <a
  3932    href="#font-variant-position-normal-value"
  3933    title="normal!!font-variant-position">‘<code
  3934    class=property>normal</code>’</a>.</p>
  3935   <!-- due to lack of consensus, couldn't resolve on exact positioning of text decorations:
  3936 http://www.w3.org/2013/06/06-css-minutes.html#item03 -->
  3938   <p>Because of these limitations, ‘<a
  3939    href="#propdef-font-variant-position"><code
  3940    class=property>font-variant-position</code></a>’ is not recommended for
  3941    use in user agent stylesheets. Authors should use it in cases where
  3942    subscripts or superscripts will only contain the narrow range of
  3943    characters supported by the fonts specified.
  3945   <p class=note>The variant glyphs use the same baseline as the default
  3946    glyphs would use. There is no shift in the placement along the baseline,
  3947    so the use of variant glyphs doesn't affect the height of the inline box
  3948    or alter the height of the linebox. This makes superscript and subscript
  3949    variants ideal for situations where it's important that leading remain
  3950    constant, such as in multi-column layout.
  3952   <div class=example>
  3953    <p>A typical user agent default style for the <a class=tag
  3954     href="#sub">sub</a> element:</p>
  3956    <pre>sub {
  3957   vertical-align: sub;
  3958   font-size: smaller;
  3959   line-height: normal;
  3961 </pre>
  3963    <p>Using font-variant-position to specify typographic subscripts in a way
  3964     that will still show subscripts in older user agents:</p>
  3966    <pre>@supports ( font-variant-position: sub ) {
  3968   sub {
  3969     vertical-align: baseline;
  3970     font-size: 100%;
  3971     line-height: inherit;
  3972     font-variant-position: sub;
  3976 </pre>
  3978    <p>User agents that support the ‘<a
  3979     href="#propdef-font-variant-position"><code
  3980     class=property>font-variant-position</code></a>’ property will select a
  3981     subscript variant glyph and render this without adjusting the baseline or
  3982     font-size. Older user agents will ignore the ‘<a
  3983     href="#propdef-font-variant-position"><code
  3984     class=property>font-variant-position</code></a>’ property definition
  3985     and use the standard defaults for subscripts.</p>
  3986   </div>
  3987   <!-- prop: font-variant-caps -->
  3989   <h3 id=font-variant-caps-prop><span class=secno>6.6 </span>Capitalization:
  3990    the <a href="#propdef-font-variant-caps">font-variant-caps</a> property</h3>
  3992   <table class=propdef id=namefont-variant-capsvaluenormal-small-c>
  3993    <tbody>
  3994     <tr>
  3995      <td>Name:
  3997      <td><dfn id=propdef-font-variant-caps>font-variant-caps</dfn>
  3999     <tr>
  4000      <td>Value:
  4002      <td><a href="#font-variant-caps-normal-value"
  4003       title="normal!!font-variant-caps">normal</a> | <a
  4004       href="#small-caps">small-caps</a> | <a
  4005       href="#all-small-caps">all-small-caps</a> | <a
  4006       href="#petite-caps">petite-caps</a> | <a
  4007       href="#all-petite-caps">all-petite-caps</a> | <a
  4008       href="#unicase">unicase</a> | <a href="#titling-caps">titling-caps</a>
  4010     <tr>
  4011      <td>Initial:
  4013      <td>normal
  4015     <tr>
  4016      <td>Applies to:
  4018      <td>all elements
  4020     <tr>
  4021      <td>Inherited:
  4023      <td>yes
  4025     <tr>
  4026      <td>Percentages:
  4028      <td>N/A
  4030     <tr>
  4031      <td>Media:
  4033      <td>visual
  4035     <tr>
  4036      <td>Computed value:
  4038      <td>as specified
  4040     <tr>
  4041      <td>Animatable:
  4043      <td>no
  4044   </table>
  4046   <p>This property allows the selection of alternate glyphs used for small or
  4047    petite capitals or for titling. These glyphs are specifically designed to
  4048    blend well with the surrounding normal glyphs, to maintain the weight and
  4049    readability which suffers when text is simply resized to fit this purpose.
  4051   <p>Individual values have the following meanings:
  4053   <dl>
  4054    <dt><dfn id=font-variant-caps-normal-value
  4055     title="normal!!font-variant-caps">normal</dfn>
  4057    <dd>None of the features listed below are enabled.
  4059    <dt><dfn id=small-caps>small-caps</dfn>
  4061    <dd>Enables display of small capitals (OpenType feature: <span
  4062     class=tag>smcp</span>). Small-caps glyphs typically use the form of
  4063     uppercase letters but are reduced to the size of lowercase letters.
  4064   </dl>
  4066   <div class=featex><img alt="small-caps example" src=smcp.png></div>
  4068   <dl>
  4069    <dt><dfn id=all-small-caps>all-small-caps</dfn>
  4071    <dd>Enables display of small capitals for both upper and lowercase letters
  4072     (OpenType features: <span class=tag>c2sc, smcp</span>).
  4074    <dt><dfn id=petite-caps>petite-caps</dfn>
  4076    <dd>Enables display of petite capitals (OpenType feature: <span
  4077     class=tag>pcap</span>).
  4079    <dt><dfn id=all-petite-caps>all-petite-caps</dfn>
  4081    <dd>Enables display of petite capitals for both upper and lowercase
  4082     letters (OpenType features: <span class=tag>c2pc, pcap</span>).
  4084    <dt><dfn id=unicase>unicase</dfn>
  4086    <dd>Enables display of mixture of small capitals for uppercase letters
  4087     with normal lowercase letters (OpenType feature: <span
  4088     class=tag>unic</span>).
  4090    <dt><dfn id=titling-caps>titling-caps</dfn>
  4092    <dd>Enables display of titling capitals (OpenType feature: <span
  4093     class=tag>titl</span>). Uppercase letter glyphs are often designed for
  4094     use with lowercase letters. When used in all uppercase titling sequences
  4095     they can appear too strong. Titling capitals are designed specifically
  4096     for this situation.
  4097   </dl>
  4099   <p>The availability of these glyphs is based on whether a given feature is
  4100    defined or not in the feature list of the font. User agents can optionally
  4101    decide this on a per-script basis but should explicitly not decide this on
  4102    a per-character basis.
  4104   <p>Some fonts may only support a subset or none of the features described
  4105    for this property. For backwards compatibility with CSS 2.1, if ‘<a
  4106    href="#small-caps"><code class=property>small-caps</code></a>’ or ‘<a
  4107    href="#all-small-caps"><code class=property>all-small-caps</code></a>’
  4108    is specified but small-caps glyphs are not available for a given font,
  4109    user agents should simulate a small-caps font, for example by taking a
  4110    normal font and replacing the glyphs for lowercase letters with scaled
  4111    versions of the glyphs for uppercase characters (replacing the glyphs for
  4112    both upper and lowercase letters in the case of ‘<a
  4113    href="#all-small-caps"><code class=property>all-small-caps</code></a>’).
  4115   <div class=figure style="padding: 0; margin: auto;"><img alt="synthetic vs.
  4116    real small-caps" class=hires src=synthetic-vs-real-small-caps.png
  4117    width=512px>
  4118    <p class=caption>Synthetic vs. real small-caps
  4119   </div>
  4121   <p>To match the surrounding text, a font may provide alternate glyphs for
  4122    caseless characters when these features are enabled but when a user agent
  4123    simulates small capitals, it must not attempt to simulate alternates for
  4124    codepoints which are considered caseless.
  4126   <div class=figure style="padding: 0; margin: auto;"><img alt="caseless
  4127    characters with small-caps, all-small-caps enabled" class=hires
  4128    src=small-capitals-variations.png width=418px>
  4129    <p class=caption>Caseless characters with small-caps, all-small-caps
  4130     enabled
  4131   </div>
  4133   <p>If either ‘<a href="#petite-caps"><code
  4134    class=property>petite-caps</code></a>’ or ‘<a
  4135    href="#all-petite-caps"><code class=property>all-petite-caps</code></a>’
  4136    is specified for a font that doesn't support these features, the property
  4137    behaves as if ‘<a href="#small-caps"><code
  4138    class=property>small-caps</code></a>’ or ‘<a
  4139    href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
  4140    respectively, had been specified. If ‘<a href="#unicase"><code
  4141    class=property>unicase</code></a>’ is specified for a font that doesn't
  4142    support that feature, the property behaves as if ‘<a
  4143    href="#small-caps"><code class=property>small-caps</code></a>’ was
  4144    applied only to lowercased uppercase letters. If ‘<a
  4145    href="#titling-caps"><code class=property>titling-caps</code></a>’ is
  4146    specified with a font that does not support this feature, this property
  4147    has no visible effect. When simulated small capital glyphs are used, for
  4148    scripts that lack uppercase and lowercase letters, ‘<a
  4149    href="#small-caps"><code class=property>small-caps</code></a>’, ‘<a
  4150    href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
  4151    ‘<a href="#petite-caps"><code class=property>petite-caps</code></a>’,
  4152    ‘<a href="#all-petite-caps"><code
  4153    class=property>all-petite-caps</code></a>’ and ‘<a
  4154    href="#unicase"><code class=property>unicase</code></a>’ have no visible
  4155    effect.
  4157   <p>When casing transforms are used to simulate small capitals, the casing
  4158    transformations must match those used for the <span
  4159    class=property>‘<code class=property>text-transform</code>’</span>
  4160    property.
  4162   <p>As a last resort, unscaled uppercase letter glyphs in a normal font may
  4163    replace glyphs in a small-caps font so that the text appears in all
  4164    uppercase letters.
  4166   <div class=figure style="padding: 0; margin: auto;"><img alt="using
  4167    all-small-caps in acronym-laden text" class=hires
  4168    src=acronym-laden-text.png width=596px>
  4169    <p class=caption>Using small capitals to improve readability in
  4170     acronym-laden text
  4171   </div>
  4173   <div class=example>
  4174    <p>Quotes rendered italicised, with small-caps on the first line:</p>
  4176    <pre>blockquote            { font-style: italic; }
  4177 blockquote:first-line { font-variant: small-caps; }
  4179 &lt;blockquote><a href="http://lists.w3.org/Archives/Public/www-style/2009Dec/0036.html" style="text-decoration: none">I'll be honor-bound to slap them like a haddock.</a>&lt;/blockquote>
  4180 </pre>
  4181   </div>
  4182   <!-- prop: font-variant-numeric -->
  4184   <h3 id=font-variant-numeric-prop><span class=secno>6.7 </span>Numerical
  4185    formatting: the <a
  4186    href="#propdef-font-variant-numeric">font-variant-numeric</a> property</h3>
  4188   <table class=propdef id=namefont-variant-numericvaluenormal-ltnu>
  4189    <tbody>
  4190     <tr>
  4191      <td>Name:
  4193      <td><dfn id=propdef-font-variant-numeric>font-variant-numeric</dfn>
  4195     <tr>
  4196      <td>Value:
  4198      <td><a href="#font-variant-numeric-normal-value"
  4199       title="normal!!font-variant-numeric">normal</a> | [ <a
  4200       href="#numeric-figure-values"><var>&lt;numeric-figure-values&gt;</var></a>
  4201       || <a
  4202       href="#numeric-spacing-values"><var>&lt;numeric-spacing-values&gt;</var></a>
  4203       || <a
  4204       href="#numeric-fraction-values"><var>&lt;numeric-fraction-values&gt;</var></a>
  4205       || <a href="#ordinal">ordinal</a> || <a
  4206       href="#slashed-zero">slashed-zero</a> ]
  4208     <tr>
  4209      <td>Initial:
  4211      <td>normal
  4213     <tr>
  4214      <td>Applies to:
  4216      <td>all elements
  4218     <tr>
  4219      <td>Inherited:
  4221      <td>yes
  4223     <tr>
  4224      <td>Percentages:
  4226      <td>N/A
  4228     <tr>
  4229      <td>Media:
  4231      <td>visual
  4233     <tr>
  4234      <td>Computed value:
  4236      <td>as specified
  4238     <tr>
  4239      <td>Animatable:
  4241      <td>no
  4242   </table>
  4244   <p>Specifies control over numerical forms. The example below shows how some
  4245    of these values can be combined to influence the rendering of tabular data
  4246    with fonts that support these features. Within normal paragraph text,
  4247    proportional numbers are used while tabular numbers are used so that
  4248    columns of numbers line up properly:
  4250   <div class=figure style="padding: 0; margin: auto;"><img alt="combining
  4251    number styles" src=numberstyles.png>
  4252    <p class=caption>Using number styles
  4253   </div>
  4255   <p>Possible combinations:
  4257   <pre
  4258    class=prod><dfn id=numeric-figure-values><var>&lt;numeric-figure-values&gt;</var></dfn>   = [ <a href="#lining-nums">lining-nums</a> | <a href="#oldstyle-nums">oldstyle-nums</a> ]</pre>
  4260   <pre
  4261    class=prod><dfn id=numeric-spacing-values><var>&lt;numeric-spacing-values&gt;</var></dfn>  = [ <a href="#proportional-nums">proportional-nums</a> | <a href="#tabular-nums">tabular-nums</a> ]</pre>
  4263   <pre
  4264    class=prod><dfn id=numeric-fraction-values><var>&lt;numeric-fraction-values&gt;</var></dfn> = [ <a href="#diagonal-fractions">diagonal-fractions</a> | <a href="#stacked-fractions">stacked-fractions</a> ]</pre>
  4266   <p>Individual values have the following meanings:
  4268   <dl>
  4269    <dt><dfn id=font-variant-numeric-normal-value
  4270     title="normal!!font-variant-numeric">normal</dfn>
  4272    <dd>None of the features listed below are enabled.
  4274    <dt><dfn id=lining-nums>lining-nums</dfn>
  4276    <dd>Enables display of lining numerals (OpenType feature: <span
  4277     class=tag>lnum</span>).
  4279    <dt><dfn id=oldstyle-nums>oldstyle-nums</dfn>
  4281    <dd>Enables display of old-style numerals (OpenType feature: <span
  4282     class=tag>onum</span>).
  4284    <dt><dfn id=proportional-nums>proportional-nums</dfn>
  4286    <dd>Enables display of proportional numerals (OpenType feature: <span
  4287     class=tag>pnum</span>).
  4289    <dt><dfn id=tabular-nums>tabular-nums</dfn>
  4291    <dd>Enables display of tabular numerals (OpenType feature: <span
  4292     class=tag>tnum</span>).
  4294    <dt><dfn id=diagonal-fractions>diagonal-fractions</dfn>
  4296    <dd>Enables display of lining diagonal fractions (OpenType feature: <span
  4297     class=tag>frac</span>).
  4298   </dl>
  4300   <div class=featex><img alt="diagonal fraction example" src=frac.png></div>
  4302   <dl>
  4303    <dt><dfn id=stacked-fractions>stacked-fractions</dfn>
  4305    <dd>Enables display of lining stacked fractions (OpenType feature: <span
  4306     class=tag>afrc</span>).
  4307   </dl>
  4309   <div class=featex><img alt="stacked fraction example" src=afrc.png></div>
  4311   <dl>
  4312    <dt><dfn id=ordinal>ordinal</dfn>
  4314    <dd>Enables display of forms used with ordinal numbers (OpenType feature:
  4315     <span class=tag>ordn</span>).
  4317    <dt><dfn id=slashed-zero>slashed-zero</dfn>
  4319    <dd>Enables display of slashed zeros (OpenType feature: <span
  4320     class=tag>zero</span>).
  4321   </dl>
  4323   <div class=featex><img alt="slashed zero example" src=zero.png></div>
  4325   <div class=example id=steak-marinade>
  4326    <p>A simple flank steak marinade recipe, rendered with automatic fractions
  4327     and old-style numerals:</p>
  4329    <pre>.amount { font-variant-numeric: oldstyle-nums diagonal-fractions; }
  4331 &lt;h4>Steak marinade:&lt;/h4>
  4332 &lt;ul>
  4333   &lt;li>&lt;span class="amount">2&lt;/span> tbsp olive oil&lt;/li>
  4334   &lt;li>&lt;span class="amount">1&lt;/span> tbsp lemon juice&lt;/li>
  4335   &lt;li>&lt;span class="amount">1&lt;/span> tbsp soy sauce&lt;/li>
  4336   &lt;li>&lt;span class="amount">1 1/2&lt;/span> tbsp dry minced onion&lt;/li>
  4337   &lt;li>&lt;span class="amount">2 1/2&lt;/span> tsp italian seasoning&lt;/li>
  4338   &lt;li>Salt &amp;amp; pepper&lt;/li>
  4339 &lt;/ul>
  4341 &lt;p>Mix the meat with the marinade and let it sit covered in the refrigerator
  4342 for a few hours or overnight.&lt;/p>
  4343 </pre>
  4345    <p>Note that the fraction feature is only applied to values not the entire
  4346     paragraph. Fonts often implement this feature using contextual rules
  4347     based on the use of the slash (‘<code class=css>/</code>’) character.
  4348     As such, it's not suitable for use as a paragraph-level style.</p>
  4349   </div>
  4350   <!-- prop: font-variant-alternates -->
  4352   <h3 id=font-variant-alternates-prop><span class=secno>6.8 </span>Alternates
  4353    and swashes: the <a
  4354    href="#propdef-font-variant-alternates">font-variant-alternates</a>
  4355    property</h3>
  4357   <table class=propdef id=namefont-variant-alternatesvaluenormal-s>
  4358    <tbody>
  4359     <tr>
  4360      <td>Name:
  4362      <td><dfn
  4363       id=propdef-font-variant-alternates>font-variant-alternates</dfn>
  4365     <tr>
  4366      <td>Value:
  4368      <td>normal | [ <a href="#stylistic"
  4369       title=stylistic>stylistic(&lt;feature-value-name&gt;)</a> || <a
  4370       href="#historical-forms">historical-forms</a> || <a href="#styleset"
  4371       title=styleset>styleset(&lt;feature-value-name&gt; #)</a> || <a
  4372       href="#character-variant"
  4373       title=character-variant>character-variant(&lt;feature-value-name&gt;
  4374       #)</a> || <a href="#swash"
  4375       title=swash>swash(&lt;feature-value-name&gt;)</a> || <a
  4376       href="#ornaments"
  4377       title=ornaments>ornaments(&lt;feature-value-name&gt;)</a> || <a
  4378       href="#annotation"
  4379       title=annotation>annotation(&lt;feature-value-name&gt;)</a> ]
  4381     <tr>
  4382      <td>Initial:
  4384      <td>normal
  4386     <tr>
  4387      <td>Applies to:
  4389      <td>all elements
  4391     <tr>
  4392      <td>Inherited:
  4394      <td>yes
  4396     <tr>
  4397      <td>Percentages:
  4399      <td>N/A
  4401     <tr>
  4402      <td>Media:
  4404      <td>visual
  4406     <tr>
  4407      <td>Computed value:
  4409      <td>as specified
  4411     <tr>
  4412      <td>Animatable:
  4414      <td>no
  4415   </table>
  4417   <p>For any given character, fonts can provide a variety of alternate glyphs
  4418    in addition to the default glyph for that character. This property
  4419    provides control over the selection of these alternate glyphs.
  4421   <p>For many of the property values listed below, several different
  4422    alternate glyphs are available. How many alternates are available and what
  4423    they represent is font-specific, so these are each marked <dfn
  4424    id=font-specific>font specific</dfn> in the value definitions below.
  4425    Because the nature of these alternates is font-specific, the <a
  4426    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  4427    rule is used to define values for a specific font family or set of
  4428    families that associate a font-specific numeric
  4429    <code>&lt;feature-index&gt;</code> with a custom
  4430    <code>&lt;feature-value-name&gt;</code>, which is then used in this
  4431    property to select specific alternates:
  4433   <pre>@font-feature-values Noble Script { @swash { swishy: 1; flowing: 2; } }
  4435 p {
  4436   font-family: Noble Script;
  4437   font-variant-alternates: swash(flowing); /* use swash alternate #2 */
  4438 }</pre>
  4440   <p>When a particular <code>&lt;feature-value-name&gt;</code> has not been
  4441    defined for a given family or for a particular feature type, the computed
  4442    value must be the same as if it had been defined. However, property values
  4443    that contain these undefined <code>&lt;feature-value-name&gt;</code>
  4444    identifiers must be ignored when choosing glyphs.
  4446   <pre>/* these two style rules are effectively the same */
  4447 p { font-variant-alternates: swash(unknown-value); } /* not a defined value, ignored */
  4448 p { font-variant-alternates: normal; }
  4449 </pre>
  4451   <p>This allows values to be defined and used for a given set of font
  4452    families but ignored if fallback occurs, since the font family name would
  4453    be different. If a given value is outside the range supported by a given
  4454    font, the value is ignored. These values never apply to generic font
  4455    families.
  4457   <p>Individual values have the following meanings:
  4459   <dl>
  4460    <dt><dfn id=font-variant-alternates-normal-value
  4461     title="normal!!font-variant-alternates">normal</dfn>
  4463    <dd>None of the features listed below are enabled.
  4465    <dt><dfn id=historical-forms>historical-forms</dfn>
  4467    <dd>Enables display of historical forms (OpenType feature: <span
  4468     class=tag>hist</span>).
  4469   </dl>
  4471   <div class=featex><img alt="historical form example" src=hist.png></div>
  4473   <dl>
  4474    <dt><dfn id=stylistic
  4475     title=stylistic>stylistic(&lt;feature-value-name&gt;)</dfn>
  4477    <dd>Enables display of stylistic alternates (<a
  4478     href="#font-specific"><em>font specific</em></a>, OpenType feature: <span
  4479     class=tag>salt &lt;feature-index&gt;</span>).
  4480   </dl>
  4482   <div class=featex><img alt="stylistic alternate example" src=salt.png></div>
  4484   <dl>
  4485    <dt><dfn id=styleset title=styleset>styleset(&lt;feature-value-name&gt;
  4486     #)</dfn>
  4488    <dd>Enables display with stylistic sets (<a href="#font-specific"><em>font
  4489     specific</em></a>, OpenType feature: <span
  4490     class=tag>ss&lt;feature-index&gt;</span> OpenType currently defines <span
  4491     class=tag>ss01</span> through <span class=tag>ss20</span>).
  4492   </dl>
  4494   <div class=featex><img alt="styleset example" src=ssnn.png></div>
  4496   <dl>
  4497    <dt><dfn id=character-variant
  4498     title=character-variant>character-variant(&lt;feature-value-name&gt;
  4499     #)</dfn>
  4501    <dd>Enables display of specific character variants (<a
  4502     href="#font-specific"><em>font specific</em></a>, OpenType feature: <span
  4503     class=tag>cv&lt;feature-index&gt;</span> OpenType currently defines <span
  4504     class=tag>cv01</span> through <span class=tag>cv99</span>).
  4506    <dt><dfn id=swash title=swash>swash(&lt;feature-value-name&gt;)</dfn>
  4508    <dd>Enables display of swash glyphs (<a href="#font-specific"><em>font
  4509     specific</em></a>, OpenType feature: <span class=tag>swsh
  4510     &lt;feature-index&gt;, cswh &lt;feature-index&gt;</span>).
  4511   </dl>
  4513   <div class=featex><img alt="swash example" src=swsh.png></div>
  4515   <dl>
  4516    <dt><dfn id=ornaments
  4517     title=ornaments>ornaments(&lt;feature-value-name&gt;)</dfn>
  4519    <dd>Enables replacement of default glyphs with ornaments, if provided in
  4520     the font (<a href="#font-specific"><em>font specific</em></a>, OpenType
  4521     feature: <span class=tag>ornm &lt;feature-index&gt;</span>). Some fonts
  4522     may offer ornament glyphs as alternates for a wide collection of
  4523     characters; however, displaying arbitrary characters (e.g.,
  4524     alphanumerics) as ornaments is poor practice as it distorts the semantics
  4525     of the data. Font designers are encouraged to encode all ornaments
  4526     (except those explicitly encoded in the Unicode Dingbats blocks, etc.) as
  4527     alternates for the bullet character (U+2022) to allow authors to select
  4528     the desired glyph using ‘<a href="#ornaments"><code
  4529     class=property>ornaments</code></a>’.
  4530   </dl>
  4532   <div class=featex><img alt="ornaments example" src=ornm.png></div>
  4534   <dl>
  4535    <dt><dfn id=annotation
  4536     title=annotation>annotation(&lt;feature-value-name&gt;)</dfn>
  4538    <dd>Enables display of alternate annotation forms (<a
  4539     href="#font-specific"><em>font specific</em></a>, OpenType feature: <span
  4540     class=tag>nalt &lt;feature-index&gt;</span>).
  4541   </dl>
  4543   <div class=featex><img alt="alternate annotation form example"
  4544    src=nalt.png></div>
  4546   <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
  4547    specific alternates: the <dfn id=at-font-feature-values-rule
  4548    style="font-weight: inherit; font-style:
  4549    inherit"><code>@font-feature-values</code></dfn> rule</h3>
  4551   <p>Several of the possible values of ‘<a
  4552    href="#propdef-font-variant-alternates"><code
  4553    class=property>font-variant-alternates</code></a>’ listed above are
  4554    labeled as <a href="#font-specific"><em>font specific</em></a>. For these
  4555    features fonts may define not just a single glyph but a set of alternate
  4556    glyphs with an index to select a given alternate. Since these are font
  4557    family specific, the <a
  4558    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  4559    rule is used to define named values for these indices for a given family.
  4561   <p class=note>See the <a href="#om-fontfeaturevalues">object model
  4562    reference section</a> for a description of the interfaces used to modify
  4563    these rules via the CSS Object Model.
  4565   <div class=example>
  4566    <p>In the case of the swash Q in the example shown above, the swash could
  4567     be specified using these style rules:</p>
  4569    <pre>
  4571 @font-feature-values Jupiter Sans {
  4572   @swash {
  4573     delicate: 1;
  4574     flowing: 2;
  4578 h2 { font-family: Jupiter Sans, sans-serif; }
  4580 /* show the second swash variant in h2 headings */
  4581 h2:first-letter { font-variant-alternates: swash(flowing); }
  4583 &lt;h2>Quick&lt;/h2></pre>
  4585    <p>When Jupiter Sans is present, the second alternate swash alternate will
  4586     be displayed. When not present, no swash character will be shown, since
  4587     the specific named value "flowing" is only defined for the Jupiter Sans
  4588     family. The @-mark indicates the name of the property value for which a
  4589     named value can be used. The name "flowing" is chosen by the author. The
  4590     index that represents each alternate is defined within a given font's
  4591     data.</p>
  4592   </div>
  4594   <h4 id=basic-syntax><span class=secno>6.9.1 </span>Basic syntax</h4>
  4596   <p>An <a
  4597    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  4598    rule is composed of a list of font families followed by a block containing
  4599    individual <a href="#featurevalueblock"><i
  4600    title="feature_value_block">feature value blocks</i></a> that take the
  4601    form of @-rules. Each block defines a set of named values for a specific
  4602    font feature when a given set of font families is used. Effectively, they
  4603    define a mapping of ⟨family, feature, ident⟩ → ⟨values⟩ where
  4604    ⟨values⟩ are the numeric indices used for specific features defined
  4605    for a given font.
  4607   <p>In terms of the grammar, this specification defines the following
  4608    productions:
  4610   <pre><dfn id=fontfeaturevaluesrule>font_feature_values_rule</dfn>
  4611   : <a href="#fontfeaturevaluessym"><i>FONT_FEATURE_VALUES_SYM</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#fontfamilynamelist"><i>font_family_name_list</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
  4612     '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevalueblock"><i>feature_value_block</i></a>? [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevalueblock"><i>feature_value_block</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
  4615 <dfn id=fontfamilynamelist>font_family_name_list</dfn>
  4616   : <a href="#fontfamilyname"><i>font_family_name</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ',' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#fontfamilyname"><i>font_family_name</i></a> ]*
  4619 <dfn id=fontfamilyname>font_family_name</dfn>
  4620   : <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>STRING</i></a> | [ <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> ]* ]
  4623 <dfn id=featurevalueblock>feature_value_block</dfn>
  4624   : <a href="#featuretype"><i>feature_type</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
  4625     '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevaluedefinition"><i>feature_value_definition</i></a>? [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ';' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevaluedefinition"><i>feature_value_definition</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
  4628 <dfn id=featuretype>feature_type</dfn>:
  4629   <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>ATKEYWORD</i></a>
  4632 <dfn id=featurevaluedefinition>feature_value_definition</dfn>
  4633   : <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ':' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>NUMBER</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>NUMBER</i></a> ]*
  4635 </pre>
  4637   <p>The following new token is introduced:
  4639   <pre>@{F}{O}{N}{T}{-}{F}{E}{A}{T}{U}{R}{E}{-}{V}{A}{L}{U}{E}{S}   {return <dfn id=fontfeaturevaluessym>FONT_FEATURE_VALUES_SYM</dfn>;}
  4640 </pre>
  4642   <p><a href="#featurevalueblock"><i title="feature_value_block">Feature
  4643    value blocks</i></a> are handled as <a
  4644    href="http://www.w3.org/TR/CSS2/syndata.html#at-rules">at-rules</a>, they
  4645    consist of everything up to the next block or semi-colon, whichever comes
  4646    first.
  4648   <p>The <a href="#fontfamilynamelist"><i title="font_family_name_list">font
  4649    family list</i></a> is a comma-delimited list of <a
  4650    href="#fontfamilyname"><i title="font_family_name">font family
  4651    names</i></a> that match the definition of <a
  4652    href="#family-name-value"><var>&lt;family-name&gt;</var></a> for the <a
  4653    href="#propdef-font-family" title="font-family!!property">‘<code
  4654    class=property>font-family</code>’</a> property. This means that only
  4655    named font families are allowed, rules that include generic or system
  4656    fonts in the list of font families are syntax errors. However, if a user
  4657    agent defines a generic font to be a specific named font (e.g. Helvetica),
  4658    the settings associated with that family name will be used. If syntax
  4659    errors occur within the font family list, the entire rule must be ignored.
  4661   <p>Within <a href="#featurevalueblock"><i
  4662    title="feature_value_block">feature value blocks</i></a>, the <a
  4663    href="#featuretype"><i title="feature_type">feature type</i></a> is
  4664    ‘<code class=css>@</code>’ followed by the name of one of the <a
  4665    href="#font-specific"><em>font specific</em></a> property values of ‘<a
  4666    href="#propdef-font-variant-alternates"><code
  4667    class=property>font-variant-alternates</code></a>’ (e.g. <a
  4668    href="#swash"><code>@swash</code></a>). The identifiers used within
  4669    feature value definitions follow the rules of CSS user identifiers and are
  4670    case-sensitive. They are unique only for a given set of font families and
  4671    <a href="#featuretype"><i title="feature_type">feature type</i></a>. The
  4672    same identifier used with a different <a href="#featuretype"><i
  4673    title="feature_type">feature type</i></a> is treated as a separate and
  4674    distinct value. If the same identifier is defined mulitple times for a
  4675    given <a href="#featuretype"><i title="feature_type">feature type</i></a>
  4676    and font family, the last defined value is used. Values associated with a
  4677    given identifier are limited to integer values 0 or greater.
  4679   <p>When syntax errors occur within a <a href="#featurevaluedefinition"><i
  4680    title="feature_value_definition">feature value definition</i></a>, such as
  4681    invalid identifiers or values, the entire <a
  4682    href="#featurevaluedefinition"><i title="feature_value_definition">feature
  4683    value definition</i></a> must be omitted, just as syntax errors in style
  4684    declarations are handled. When the <a href="#featuretype"><i
  4685    title="feature_type">feature type</i></a> is invalid, the entire
  4686    associated <a href="#featurevalueblock"><i
  4687    title="feature_value_block">feature value block</i></a> must be ignored.
  4689   <div class=example>
  4690    <p>Rules that are equivalent given syntax error handling:</p>
  4692    <pre>@font-feature-values Bongo {
  4693   @swash { ornate: 1; }
  4694   annotation { boxed: 4; } /* should be @annotation! */
  4695   @swash { double-loops: 1; flowing: -1; } /* negative value */
  4696   @ornaments ; /* incomplete definition */
  4697   @styleset { double-W: 14; sharp-terminals: 16 1 } /* missing ; */
  4698   <a href="http://www.angryalien.com/0504/shiningbunnies.html" style="text-decoration: none; border: none;">redrum</a>  /* random editing mistake */
  4699 }</pre>
  4701    <p>The example above is equivalent to:</p>
  4703    <pre>@font-feature-values Bongo {
  4704   @swash { ornate: 1; }
  4705   @swash { double-loops: 1; }
  4706   @styleset { double-W: 14; sharp-terminals: 16 1; }
  4707 }</pre>
  4708   </div>
  4710   <p>If multiple <a
  4711    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  4712    rules are defined for a given family, the resulting values definitions are
  4713    the union of the definitions contained within these rules. This allows a
  4714    set of named values to be defined for a given font family globally for a
  4715    site and specific additions made per-page.
  4717   <div class=example>
  4718    <p>Using both site-wide and per-page feature values:</p>
  4720    <pre>
  4721 site.css:
  4723   @font-feature-values Mercury Serif {
  4724     @styleset {
  4725       stacked-g: 3; /* "two-storey" versions of g, a */
  4726       stacked-a: 4;
  4730 page.css:
  4732   @font-feature-values Mercury Serif {
  4733     @styleset {
  4734       geometric-m: 7; /* alternate version of m */
  4738   body {
  4739     font-family: Mercury Serif, serif;
  4741     /* enable both the use of stacked g and alternate m */
  4742     font-variant-alternates: styleset(stacked-g, geometric-m);
  4743   }</pre>
  4744   </div>
  4746   <div class=example>
  4747    <p>Using a commonly named value allows authors to use a single style rule
  4748     to cover a set of fonts for which the underlying selector is different
  4749     for each font. If either font in the example below is found, a circled
  4750     number glyph will be used:</p>
  4752    <pre>@font-feature-values Taisho Gothic {
  4753   @annotation { boxed: 1; circled: 4; }
  4756 @font-feature-values Otaru Kisa {
  4757   @annotation { circled: 1; black-boxed: 3; }
  4760 h3.title {
  4761   /* circled form defined for both fonts */
  4762   font-family: Taisho Gothic, Otaru Kisa;
  4763   font-variant: annotation(circled);
  4764 }</pre>
  4765   </div>
  4767   <h4 id=multi-valued-feature-value-definitions><span class=secno>6.9.2
  4768    </span>Multi-valued feature value definitions</h4>
  4770   <p>Most <a href="#font-specific"><em>font specific</em></a> ‘<a
  4771    href="#propdef-font-variant-alternates"><code
  4772    class=property>font-variant-alternates</code></a>’ property values take
  4773    a single value (e.g. ‘<a href="#swash"><code
  4774    class=property>swash</code></a>’). The ‘<a
  4775    href="#character-variant"><code
  4776    class=property>character-variant</code></a>’ property value allows two
  4777    values and ‘<a href="#styleset"><code
  4778    class=property>styleset</code></a>’ allows an unlimited number.
  4780   <p>For the styleset property value, multiple values indicate the style sets
  4781    to be enabled. Values between 1 and 99 enable OpenType features <span
  4782    class=tag>ss01</span> through <span class=tag>ss99</span>. However, the
  4783    OpenType standard only officially defines <span class=tag>ss01</span>
  4784    through <span class=tag>ss20</span>. For OpenType fonts, values greater
  4785    than 99 or equal to 0 do not generate a syntax error when parsed but
  4786    enable no OpenType features.
  4788   <pre>@font-feature-values Mars Serif {
  4789   @styleset {
  4790     alt-g: 1;        /* implies ss01 = 1 */
  4791     curly-quotes: 3; /* implies ss03 = 1 */
  4792     code: 4 5;       /* implies ss04 = 1, ss05 = 1 */
  4795   @styleset {
  4796     dumb: 125;        /* &gt;99, ignored */
  4799   @swash {
  4800     swishy: 3 5;     /* more than 1 value for swash, syntax error */
  4804 p.codeblock {
  4805   /* implies ss03 = 1, ss04 = 1, ss05 = 1 */
  4806   font-variant-alternates: styleset(curly-quotes, code);
  4807 }</pre>
  4809   <p>For character-variant, a single value between 1 and 99 indicates the
  4810    enabling of OpenType feature <span class=tag>cv01</span> through <span
  4811    class=tag>cv99</span>. For OpenType fonts, values greater than 99 or equal
  4812    to 0 are ignored but do not generate a syntax error when parsed but enable
  4813    no OpenType features. When two values are listed, the first value
  4814    indicates the feature used and the second the value passed for that
  4815    feature. If more than two values are assigned to a given name, a syntax
  4816    error occurs and the entire <a href="#featurevaluedefinition"><i
  4817    title="feature_value_definition">feature value definition</i></a> is
  4818    ignored.
  4820   <pre>@font-feature-values MM Greek {
  4821   @character-variant { alpha-2: 1 2; }   /* implies cv01 = 2 */
  4822   @character-variant { beta-3: 2 3; }    /* implies cv02 = 3 */
  4823   @character-variant { epsilon: 5 3 6; } /* more than 2 values, syntax error, definition ignored */
  4824   @character-variant { gamma: 12; }      /* implies cv12 = 1 */
  4825   @character-variant { zeta:   20 3; }   /* implies cv20 = 3 */
  4826   @character-variant { zeta-2: 20 2; }   /* implies cv20 = 2 */
  4827   @character-variant { silly: 105; }     /* &gt;99, ignored */
  4828   @character-variant { dumb: 323 3; }    /* &gt;99, ignored */
  4831 #title {
  4832   /* use the third alternate beta, first alternate gamma */
  4833   font-variant-alternates: character-variant(beta-3, gamma);
  4836 p {
  4837   /* zeta-2 follows zeta, implies cv20 = 2  */
  4838   font-variant-alternates: character-variant(zeta, zeta-2);
  4841 .special {
  4842   /* zeta follows zeta-2, implies cv20 = 3  */
  4843   font-variant-alternates: character-variant(zeta-2, zeta);
  4844 }</pre>
  4846   <div class=figure><img alt="Matching text on Byzantine seals using
  4847    character variants" src=byzantineseal.png>
  4848    <p class=caption>Byzantine seal text displayed with character variants
  4849   </div>
  4851   <div class=example>
  4852    <p>In the figure above, the text in red is rendered using a font
  4853     containing character variants that mimic the character forms found on a
  4854     Byzantine seal from the 8th century A.D. Two lines below is the same text
  4855     displayed in a font without variants. Note the two variants for U and N
  4856     used on the seal.</p>
  4858    <pre>@font-feature-values Athena Ruby {
  4859   @character-variant {
  4860     leo-B: 2 1;
  4861     leo-M: 13 3;
  4862     leo-alt-N: 14 1;
  4863     leo-N: 14 2;
  4864     leo-T: 20 1;
  4865     leo-U: 21 2;
  4866     leo-alt-U: 21 4;
  4870 p {
  4871   font-variant: discretionary-ligatures,
  4872                 character-variant(leo-B, leo-M, leo-N, leo-T, leo-U);
  4875 span.alt-N {
  4876   font-variant-alternates: character-variant(leo-alt-N);
  4879 span.alt-U {
  4880   font-variant-alternates: character-variant(leo-alt-U);
  4883 &lt;p>ENO....UP͞RSTU&lt;span class="alt-U">U&lt;/span>͞&lt;span class="alt-U">U&lt;/span>ΚΑΙTỤẠG̣IUPNS&lt;/p>
  4885 &lt;p>LEON|ΚΑΙCONSTA|NTI&lt;span class="alt-N">N&lt;/span>OS..|STOIBAṢ.|LIṢROM|AIO&lt;span class="alt-N">N&lt;/span>&lt;/p>
  4886 </pre>
  4887   </div>
  4889   <h3 id=font-variant-east-asian-prop><span class=secno>6.10 </span>East
  4890    Asian text rendering: the <a
  4891    href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
  4892    property</h3>
  4894   <table class=propdef id=namefont-variant-east-asianvaluenormal-l>
  4895    <tbody>
  4896     <tr>
  4897      <td>Name:
  4899      <td><dfn
  4900       id=propdef-font-variant-east-asian>font-variant-east-asian</dfn>
  4902     <tr>
  4903      <td>Value:
  4905      <td><a href="#font-variant-east-asian-normal-value"
  4906       title="normal!!font-variant-east-asian">normal</a> | [ <a
  4907       href="#east-asian-variant-values"><var>&lt;east-asian-variant-values&gt;</var></a>
  4908       || <a
  4909       href="#east-asian-width-values"><var>&lt;east-asian-width-values&gt;</var></a>
  4910       || <a href="#ruby">ruby</a> ]
  4912     <tr>
  4913      <td>Initial:
  4915      <td>normal
  4917     <tr>
  4918      <td>Applies to:
  4920      <td>all elements
  4922     <tr>
  4923      <td>Inherited:
  4925      <td>yes
  4927     <tr>
  4928      <td>Percentages:
  4930      <td>N/A
  4932     <tr>
  4933      <td>Media:
  4935      <td>visual
  4937     <tr>
  4938      <td>Computed value:
  4940      <td>as specified
  4942     <tr>
  4943      <td>Animatable:
  4945      <td>no
  4946   </table>
  4948   <p>Allows control of glyph substitution and sizing in East Asian text.
  4950   <pre
  4951    class=prod><dfn id=east-asian-variant-values><var>&lt;east-asian-variant-values&gt;</var></dfn> = [ <a href="#jis78">jis78</a> | <a href="#jis83">jis83</a> | <a href="#jis90">jis90</a> | <a href="#jis04">jis04</a> | <a href="#simplified">simplified</a> | <a href="#traditional">traditional</a> ]</pre>
  4953   <pre
  4954    class=prod><dfn id=east-asian-width-values><var>&lt;east-asian-width-values&gt;</var></dfn>   = [ <a href="#full-width">full-width</a> | <a href="#proportional-width">proportional-width</a> ]</pre>
  4956   <p>Individual values have the following meanings:
  4958   <dl>
  4959    <dt><dfn id=font-variant-east-asian-normal-value
  4960     title="normal!!font-variant-east-asian">normal</dfn>
  4962    <dd>None of the features listed below are enabled.
  4964    <dt><dfn id=jis78>jis78</dfn>
  4966    <dd>Enables rendering of JIS78 forms (OpenType feature: <span
  4967     class=tag>jp78</span>).
  4968   </dl>
  4970   <div class=featex><img alt="JIS78 form example" src=jp78.png></div>
  4972   <dl>
  4973    <dt><dfn id=jis83>jis83</dfn>
  4975    <dd>Enables rendering of JIS83 forms (OpenType feature: <span
  4976     class=tag>jp83</span>).
  4978    <dt><dfn id=jis90>jis90</dfn>
  4980    <dd>Enables rendering of JIS90 forms (OpenType feature: <span
  4981     class=tag>jp90</span>).
  4983    <dt><dfn id=jis04>jis04</dfn>
  4985    <dd>Enables rendering of JIS2004 forms (OpenType feature: <span
  4986     class=tag>jp04</span>).
  4987     <p>The various JIS variants reflect the glyph forms defined in different
  4988      Japanese national standards. Fonts generally include glyphs defined by
  4989      the most recent national standard but it's sometimes necessary to use
  4990      older variants, to match signage for example.</p>
  4992    <dt><dfn id=simplified>simplified</dfn>
  4994    <dd>Enables rendering of simplified forms (OpenType feature: <span
  4995     class=tag>smpl</span>).
  4997    <dt><dfn id=traditional>traditional</dfn>
  4999    <dd>Enables rendering of traditional forms (OpenType feature: <span
  5000     class=tag>trad</span>).
  5001   </dl>
  5003   <p>The ‘<a href="#simplified"><code
  5004    class=property>simplified</code></a>’ and ‘<a
  5005    href="#traditional"><code class=property>traditional</code></a>’ values
  5006    allow control over the glyph forms for characters which have been
  5007    simplified over time but for which the older, traditional form is still
  5008    used in some contexts. The exact set of characters and glyph forms will
  5009    vary to some degree by context for which a given font was designed.
  5011   <div class=featex><img alt="tradtional form example" src=trad.png></div>
  5013   <dl>
  5014    <dt><dfn id=full-width>full-width</dfn>
  5016    <dd>Enables rendering of full-width variants (OpenType feature: <span
  5017     class=tag>fwid</span>).
  5019    <dt><dfn id=proportional-width>proportional-width</dfn>
  5021    <dd>Enables rendering of proportionally-spaced variants (OpenType feature:
  5022     <span class=tag>pwid</span>).
  5023   </dl>
  5025   <div class=featex><img alt="proportionally spaced Japanese example"
  5026    src=pwid.png></div>
  5028   <dl>
  5029    <dt><dfn id=ruby>ruby</dfn>
  5031    <dd>Enables display of ruby variant glyphs (OpenType feature: <span
  5032     class=tag>ruby</span>). Since ruby text is generally smaller than the
  5033     associated body text, font designers can design special glyphs for use
  5034     with ruby that are more readable than scaled down versions of the default
  5035     glyphs. Only glyph selection is affected, there is no associated font
  5036     scaling or other change that affects line layout. The red ruby text below
  5037     is shown with default glyphs (top) and with ruby variant glyphs (bottom).
  5038     Note the slight difference in stroke thickness.
  5039   </dl>
  5041   <div class=featex><img alt="ruby variant example" src=rubyshinkansen.png></div>
  5043   <h3 id=font-variant-prop><span class=secno>6.11 </span>Overall shorthand
  5044    for font rendering: the <a href="#propdef-font-variant">font-variant</a>
  5045    property</h3>
  5047   <table class=propdef id=namefont-variantvaluenormal-none-ltcommo>
  5048    <tbody>
  5049     <tr>
  5050      <td>Name:
  5052      <td><dfn id=propdef-font-variant
  5053       title="font-variant!!property">font-variant</dfn>
  5055     <tr>
  5056      <td>Value:
  5058      <td><a href="#font-variant-normal-value"
  5059       title="normal!!font-variant">normal</a> | <a
  5060       href="#font-variant-none-value" title="none!!font-variant">none</a> | [
  5061       <a href="#common-lig-values"><var>&lt;common-lig-values&gt;</var></a>
  5062       || <a
  5063       href="#discretionary-lig-values"><var>&lt;discretionary-lig-values&gt;</var></a>
  5064       || <a
  5065       href="#historical-lig-values"><var>&lt;historical-lig-values&gt;</var></a>
  5066       || <a
  5067       href="#contextual-alt-values"><var>&lt;contextual-alt-values&gt;</var></a>
  5068       || <a href="#stylistic"><var
  5069       title=stylistic>stylistic(&lt;feature-value-name&gt;)</var></a> || <a
  5070       href="#historical-forms"><var>historical-forms</var></a> || <a
  5071       href="#styleset"><var
  5072       title=styleset>styleset(&lt;feature-value-name&gt; #)</var></a> || <a
  5073       href="#character-variant"><var
  5074       title=character-variant>character-variant(&lt;feature-value-name&gt;
  5075       #)</var></a> || <a href="#swash"><var
  5076       title=swash>swash(&lt;feature-value-name&gt;)</var></a> || <a
  5077       href="#ornaments"><var
  5078       title=ornaments>ornaments(&lt;feature-value-name&gt;)</var></a> || <a
  5079       href="#annotation"><var
  5080       title=annotation>annotation(&lt;feature-value-name&gt;)</var></a> || [
  5081       <a href="#small-caps"><i>small-caps</i></a> | <a
  5082       href="#all-small-caps"><i>all-small-caps</i></a> | <a
  5083       href="#petite-caps"><i>petite-caps</i></a> | <a
  5084       href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
  5085       href="#unicase"><i>unicase</i></a> | <a
  5086       href="#titling-caps"><i>titling-caps</i></a> ] || <a
  5087       href="#numeric-figure-values"><var>&lt;numeric-figure-values&gt;</var></a>
  5088       || <a
  5089       href="#numeric-spacing-values"><var>&lt;numeric-spacing-values&gt;</var></a>
  5090       || <a
  5091       href="#numeric-fraction-values"><var>&lt;numeric-fraction-values&gt;</var></a>
  5092       || <a href="#ordinal"><i>ordinal</i></a> || <a
  5093       href="#slashed-zero"><i>slashed-zero</i></a> || <a
  5094       href="#east-asian-variant-values"><var>&lt;east-asian-variant-values&gt;</var></a>
  5095       || <a
  5096       href="#east-asian-width-values"><var>&lt;east-asian-width-values&gt;</var></a>
  5097       || <a href="#ruby"><i>ruby</i></a> ]
  5099     <tr>
  5100      <td>Initial:
  5102      <td>normal
  5104     <tr>
  5105      <td>Applies to:
  5107      <td>all elements
  5109     <tr>
  5110      <td>Inherited:
  5112      <td>yes
  5114     <tr>
  5115      <td>Percentages:
  5117      <td>see individual properties
  5119     <tr>
  5120      <td>Media:
  5122      <td>visual
  5124     <tr>
  5125      <td>Computed value:
  5127      <td>see individual properties
  5129     <tr>
  5130      <td>Animatable:
  5132      <td>see individual properties
  5133   </table>
  5135   <p>The <a href="#propdef-font-variant"
  5136    title="font-variant!!property">‘<code
  5137    class=property>font-variant</code>’</a> property is a shorthand for all
  5138    font-variant subproperties. The value <dfn id=font-variant-normal-value
  5139    title="normal!!font-variant">‘<code
  5140    class=property>normal</code>’</dfn> resets all subproperties of <a
  5141    href="#propdef-font-variant" title="font-variant!!property">‘<code
  5142    class=property>font-variant</code>’</a> to their inital value. The <dfn
  5143    id=font-variant-none-value title="none!!font-variant">‘<code
  5144    class=property>none</code>’</dfn> value sets ‘<a
  5145    href="#propdef-font-variant-ligatures"><code
  5146    class=property>font-variant-ligatures</code></a>’ to ‘<code
  5147    class=property>none</code>’ and resets all other font feature properties
  5148    to their initial value. Like other shorthands, using <a
  5149    href="#propdef-font-variant" title="font-variant!!property">‘<code
  5150    class=property>font-variant</code>’</a> resets unspecified <a
  5151    href="#propdef-font-variant" title="font-variant!!property">‘<code
  5152    class=property>font-variant</code>’</a> subproperties to their initial
  5153    values. It does not reset the values of either ‘<a
  5154    href="#propdef-font-language-override"><code
  5155    class=property>font-language-override</code></a>’ or <a
  5156    href="#propdef-font-feature-settings"
  5157    title="font-feature-settings!!property">‘<code
  5158    class=property>font-feature-settings</code>’</a>.
  5160   <h3 id=font-feature-settings-prop><span class=secno>6.12 </span>Low-level
  5161    font feature settings control: the <a
  5162    href="#propdef-font-feature-settings">font-feature-settings</a> property</h3>
  5164   <table class=propdef id=namefont-feature-settingsvaluenormal-ltf>
  5165    <tbody>
  5166     <tr>
  5167      <td>Name:
  5169      <td><dfn id=propdef-font-feature-settings
  5170       title="font-feature-settings!!property">font-feature-settings</dfn>
  5172     <tr>
  5173      <td>Value:
  5175      <td><a href="#font-feature-settings-normal-value"
  5176       title="normal!!font-feature-settings">normal</a> | <a
  5177       href="#feature-tag-value"><var>&lt;feature-tag-value&gt;</var></a> #
  5179     <tr>
  5180      <td>Initial:
  5182      <td>normal
  5184     <tr>
  5185      <td>Applies to:
  5187      <td>all elements
  5189     <tr>
  5190      <td>Inherited:
  5192      <td>yes
  5194     <tr>
  5195      <td>Percentages:
  5197      <td>N/A
  5199     <tr>
  5200      <td>Media:
  5202      <td>visual
  5204     <tr>
  5205      <td>Computed value:
  5207      <td>as specified
  5209     <tr>
  5210      <td>Animatable:
  5212      <td>no
  5213   </table>
  5215   <p>This property provides low-level control over OpenType font features. It
  5216    is intended as a way of providing access to font features that are not
  5217    widely used but are needed for a particular use case.
  5219   <p>Authors should generally use <a href="#propdef-font-variant"
  5220    title="font-variant!!property">‘<code
  5221    class=property>font-variant</code>’</a> and its related subproperties
  5222    whenever possible and only use this property for special cases where its
  5223    use is the only way of accessing a particular infrequently used font
  5224    feature.
  5226   <pre>/* enable small caps and use second swash alternate */
  5227 font-feature-settings: "smcp", "swsh" 2;</pre>
  5229   <p>A value of <dfn id=font-feature-settings-normal-value
  5230    title="normal!!font-feature-settings">‘<code
  5231    class=property>normal</code>’</dfn> means that no change in glyph
  5232    selection or positioning occurs due to this property.
  5234   <p>Feature tag values have the following syntax:
  5236   <pre
  5237    class=prod><dfn id=feature-tag-value><var>&lt;feature-tag-value&gt;</var></dfn> = &lt;string&gt; [ &lt;integer&gt; | on | off ]?</pre>
  5239   <p>The &lt;string&gt; is a case-sensitive OpenType feature tag. As
  5240    specified in the OpenType specification, feature tags contain four ASCII
  5241    characters. Tag strings longer or shorter than four characters, or
  5242    containing characters outside the U+20–7E codepoint range are invalid.
  5243    Feature tags need only match a feature tag defined in the font, so they
  5244    are not limited to explicitly registered OpenType features. Fonts defining
  5245    custom feature tags should follow the <a
  5246    href="http://www.microsoft.com/typography/otspec/featuretags.htm">tag name
  5247    rules</a> defined in the OpenType specification <a
  5248    href="#OPENTYPE-FEATURES"
  5249    rel=biblioentry>[OPENTYPE-FEATURES]<!--{{!OPENTYPE-FEATURES}}--></a>.
  5250    Feature tags not present in the font are ignored; a user agent must not
  5251    attempt to synthesize fallback behavior based on these feature tags.
  5253   <p>This means that explicitly disabling the <span class=tag>kern</span>
  5254    feature will not affect the application of kerning data found in the
  5255    ‘<code class=property>kern</code>’ table (as opposed to kerning data
  5256    associated with the <span class=tag>kern</span> feature in the ‘<code
  5257    class=property>GPOS</code>’ table). Authors should use the ‘<a
  5258    href="#propdef-font-kerning"><code
  5259    class=property>font-kerning</code></a>’ property to explictly enable or
  5260    disable kerning since this property affects both types of kerning.
  5262   <p>If present, a value indicates an index used for glyph selection. An
  5263    &lt;integer&gt; value must be 0 or greater. A value of 0 indicates that
  5264    the feature is disabled. For boolean features, a value of 1 enables the
  5265    feature. For non-boolean features, a value of 1 or greater enables the
  5266    feature and indicates the feature selection index. A value of ‘<code
  5267    class=property>on</code>’ is synonymous with 1 and ‘<code
  5268    class=property>off</code>’ is synonymous with 0. If the value is
  5269    omitted, a value of 1 is assumed.
  5271   <pre>
  5272 font-feature-settings: "dlig" 1;       /* dlig=1 enable discretionary ligatures */
  5273 font-feature-settings: "smcp" on;      /* smcp=1 enable small caps */
  5274 font-feature-settings: 'c2sc';         /* c2sc=1 enable caps to small caps */
  5275 font-feature-settings: "liga" off;     /* liga=0 no common ligatures */
  5276 font-feature-settings: "tnum", 'hist'; /* tnum=1, hist=1 enable tabular numbers and historical forms */
  5277 font-feature-settings: "tnum" "hist";  /* invalid, need a comma-delimited list */
  5278 font-feature-settings: "palin" off;    /* good idea but invalid tagname */
  5279 font-feature-settings: "PKRN";         /* PKRN=1 enable custom feature */
  5280 font-feature-settings: dlig;           /* invalid, tag must be a string */
  5281 </pre>
  5283   <p>When values greater than the range supported by the font are specified,
  5284    the behavior is explicitly undefined. For boolean features, in general
  5285    these will enable the feature. For non-boolean features, out of range
  5286    values will in general be equivalent to a 0 value. However, in both cases
  5287    the exact behavior will depend upon the way the font is designed
  5288    (specifically, which type of lookup is used to define the feature).
  5290   <p>Although specifically defined for OpenType feature tags, feature tags
  5291    for other modern font formats that support font features may be added in
  5292    the future. Where possible, features defined for other font formats should
  5293    attempt to follow the pattern of registered OpenType tags.
  5295   <div class=example>
  5296    <p>The Japanese text below will be rendered with half-width kana
  5297     characters:</p>
  5299    <pre lang=ja>
  5300 body { font-feature-settings: "hwid"; /* Half-width OpenType feature */ }
  5302 &lt;p>毎日<a href="http://images.google.com/images?q=%E3%82%AB%E3%83%AC%E3%83%BC" style="text-decoration: none;">カレー</a>食べてるのに、飽きない&lt;/p>
  5303 </pre>
  5304   </div>
  5306   <h3 id=font-language-override-prop><span class=secno>6.13 </span>Font
  5307    language override: the <a
  5308    href="#propdef-font-language-override">font-language-override</a> property</h3>
  5310   <table class=propdef id=namefont-language-overridevaluenormal-lt>
  5311    <tbody>
  5312     <tr>
  5313      <td>Name:
  5315      <td><dfn id=propdef-font-language-override>font-language-override</dfn>
  5317     <tr>
  5318      <td>Value:
  5320      <td><a href="#font-language-override-normal-value"
  5321       title="normal!!font-language-override">normal</a> | <a
  5322       href="#font-language-override-string-value"><var>&lt;string&gt;</var></a>
  5324     <tr>
  5325      <td>Initial:
  5327      <td><a href="#font-language-override-normal-value"
  5328       title="normal!!font-language-override">normal</a>
  5330     <tr>
  5331      <td>Applies to:
  5333      <td>all elements
  5335     <tr>
  5336      <td>Inherited:
  5338      <td>yes
  5340     <tr>
  5341      <td>Percentages:
  5343      <td>N/A
  5345     <tr>
  5346      <td>Media:
  5348      <td>visual
  5350     <tr>
  5351      <td>Computed value:
  5353      <td>as specified
  5355     <tr>
  5356      <td>Animatable:
  5358      <td>no
  5359   </table>
  5361   <p>Normally, authors can control the use of language-specific glyph
  5362    substitutions and positioning by setting the content language of an
  5363    element, as <a href="#language-specific-support">described above</a>:
  5365   <pre>&lt;!-- Display text using S'gaw Karen specific features -->
  5366 &ltp lang="ksw">...&lt;/p></pre>
  5368   <p>In some cases, authors may need to specify a language system that
  5369    differs from the content language, for example due to the need to mimic
  5370    another language's typographic traditions. The ‘<a
  5371    href="#propdef-font-language-override"><code
  5372    class=property>font-language-override</code></a>’ property allows
  5373    authors to explicitly specify the language system of the font, overriding
  5374    the language system implied by the content language.
  5376   <p>Values have the following meanings:
  5378   <dl>
  5379    <dt><dfn id=font-language-override-normal-value
  5380     title="normal!!font-language-override">normal</dfn>
  5382    <dd>specifies that when rendering with OpenType fonts, the content
  5383     language of the element is used to infer the OpenType language system
  5385    <dt><dfn
  5386     id=font-language-override-string-value><var>&lt;string&gt;</var></dfn>
  5388    <dd>single three-letter case-sensitive OpenType <a
  5389     href="http://www.microsoft.com/typography/otspec/languagetags.htm">language
  5390     system tag</a>, specifies the OpenType language system to be used instead
  5391     of the language system implied by the language of the element
  5392   </dl>
  5394   <p>Use of invalid OpenType language system tags must not generate a parse
  5395    error but must be ignored when doing glyph selection and placement.
  5397   <div class=example>
  5398    <p>The <a href="http://www.un.org/en/documents/udhr/index.shtml">Universal
  5399     Declaration of Human Rights</a> has been translated into a wide variety
  5400     of languages. In Turkish, Article 9 of this document might be marked up
  5401     as below:</p>
  5403    <pre lang=tr>&lt;body lang="tr">
  5405 &lt;h4>Madde 9&lt;/h4>
  5406 &lt;p>Hiç kimse keyfi olarak tutuklanamaz, alıkonulanamaz veya sürülemez.&lt;/p>
  5407 </pre>
  5409    <p>Here the user agent uses the value of the ‘<code
  5410     class=property>lang</code>’ attribute when rendering text and
  5411     appropriately renders this text without ‘<code
  5412     class=property>fi</code>’ ligatures. There is no need to use the ‘<a
  5413     href="#propdef-font-language-override"><code
  5414     class=property>font-language-override</code></a>’ property.</p>
  5416    <p>However, a given font may lack support for a specific language. In this
  5417     situation authors may need to use the typographic conventions of a
  5418     related language that are supported by that font:</p>
  5420    <pre lang=mk>&lt;body lang="mk">     &lt;!-- Macedonian lang code --&gt;
  5422 body { font-language-override: "SRB"; /* Serbian OpenType language tag */ }
  5424 &lt;h4>Члeн 9&lt;/h4>
  5425 &lt;p>Никoj чoвeк нeмa дa бидe пoдлoжeн нa прoизвoлнo aпсeњe, притвoр или прoгoнувaњe.&lt;/p>
  5427 </pre>
  5429    <p>The Macedonian text here will be rendered using Serbian typographic
  5430     conventions, with the assumption that the font specified supports
  5431     Serbian.</p>
  5432   </div>
  5434   <p><a id=rendering-considerations></a>
  5436   <h2 id=font-feature-resolution><span class=secno>7 </span>Font Feature
  5437    Resolution</h2>
  5439   <p>As described in the previous section, font features can be enabled in a
  5440    variety of ways, either via the use of <a href="#propdef-font-variant"
  5441    title="font-variant!!property">‘<code
  5442    class=property>font-variant</code>’</a> or <a
  5443    href="#propdef-font-feature-settings"
  5444    title="font-feature-settings!!property">‘<code
  5445    class=property>font-feature-settings</code>’</a> in a style rule or
  5446    within an <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
  5447    The resolution order for the union of these settings is defined below.
  5448    Features defined via CSS properties are applied on top of layout engine
  5449    default features.
  5451   <h3 id=default-features><span class=secno>7.1 </span>Default features</h3>
  5453   <p>For OpenType fonts, user agents must enable the default features defined
  5454    in the OpenType documentation for a given script and writing mode.
  5455    Required ligatures, common ligatures and contextual forms must be enabled
  5456    by default (OpenType features: <span class=tag>rlig, liga, clig,
  5457    calt</span>), along with localized forms (OpenType feature: <span
  5458    class=tag>locl</span>), and features required for proper display of
  5459    composed characters and marks (OpenType features: <span class=tag>ccmp,
  5460    mark, mkmk</span>). These features must always be enabled, even when the
  5461    value of the <a href="#propdef-font-variant"
  5462    title="font-variant!!property">‘<code
  5463    class=property>font-variant</code>’</a> and <a
  5464    href="#propdef-font-feature-settings"
  5465    title="font-feature-settings!!property">‘<code
  5466    class=property>font-feature-settings</code>’</a> properties is <span
  5467    title="normal value">‘<code class=property>normal</code>’</span>.
  5468    Individual features are only disabled when explicitly overridden by the
  5469    author, as when ‘<a href="#propdef-font-variant-ligatures"><code
  5470    class=property>font-variant-ligatures</code></a>’ is set to ‘<a
  5471    href="#no-common-ligatures"><code
  5472    class=property>no-common-ligatures</code></a>’. For handling complex
  5473    scripts such as <a
  5474    href="http://www.microsoft.com/typography/otfntdev/arabicot/features.aspx">Arabic</a>,
  5475    <a
  5476    href="http://www.microsoft.com/typography/otfntdev/mongolot/features.htm">Mongolian</a>
  5477    or <a
  5478    href="http://www.microsoft.com/typography/otfntdev/devanot/features.aspx">Devanagari</a>
  5479    additional features are required. For upright text within vertical text
  5480    runs, vertical alternates (OpenType feature: <span class=tag>vert</span>)
  5481    must be enabled.
  5483   <h3 id=feature-precedence><span class=secno>7.2 </span>Feature precedence</h3>
  5485   <p>General and <a href="#font-specific"><em>font specific</em></a> font
  5486    feature property settings are resolved in the order below, in ascending
  5487    order of precedence. This ordering is used to construct a combined list of
  5488    font features that affect a given text run.
  5490   <ol>
  5491    <li>Font features enabled by default, including features required for a
  5492     given script.
  5494    <li>If the font is defined via an <a
  5495     href="#at-font-face-rule"><code>@font-face</code></a> rule, the font
  5496     features implied by the font-variant descriptor in the <a
  5497     href="#at-font-face-rule"><code>@font-face</code></a> rule.
  5499    <li>If the font is defined via an <a
  5500     href="#at-font-face-rule"><code>@font-face</code></a> rule, the font
  5501     features implied by the font-feature-settings descriptor in the <a
  5502     href="#at-font-face-rule"><code>@font-face</code></a> rule.
  5504    <li>Feature settings determined by properties other than <a
  5505     href="#propdef-font-variant" title="font-variant!!property">‘<code
  5506     class=property>font-variant</code>’</a> or <a
  5507     href="#propdef-font-feature-settings"
  5508     title="font-feature-settings!!property">‘<code
  5509     class=property>font-feature-settings</code>’</a>. For example, setting
  5510     a non-default value for the ‘<code
  5511     class=property>letter-spacing</code>’ property disables common
  5512     ligatures.
  5514    <li>Font features implied by the value of the <a
  5515     href="#propdef-font-variant" title="font-variant!!property">‘<code
  5516     class=property>font-variant</code>’</a> property, the related <a
  5517     href="#propdef-font-variant" title="font-variant!!property">‘<code
  5518     class=property>font-variant</code>’</a> subproperties and any other CSS
  5519     property that uses OpenType features (e.g. the ‘<a
  5520     href="#propdef-font-kerning"><code
  5521     class=property>font-kerning</code></a>’ property).
  5523    <li>Font features implied by the value of <a
  5524     href="#propdef-font-feature-settings"
  5525     title="font-feature-settings!!property">‘<code
  5526     class=property>font-feature-settings</code>’</a> property.
  5527   </ol>
  5529   <p>This ordering allows authors to set up a general set of defaults for
  5530    fonts within their <a
  5531    href="#at-font-face-rule"><code>@font-face</code></a> rules, then override
  5532    them with property settings for specific elements. General property
  5533    settings override the settings in <a
  5534    href="#at-font-face-rule"><code>@font-face</code></a> rules and low-level
  5535    font feature settings override <a href="#propdef-font-variant"
  5536    title="font-variant!!property">‘<code
  5537    class=property>font-variant</code>’</a> property settings.
  5539   <p>For situations where the combined list of font feature settings contains
  5540    more than one value for the same feature, the last value is used. When a
  5541    font lacks support for a given underlying font feature, text is simply
  5542    rendered as if that font feature was not enabled; font fallback does not
  5543    occur and no attempt is made to synthesize the feature except where
  5544    explicitly defined for specific properties.
  5546   <h3 id=feature-precedence-examples><span class=secno>7.3 </span>Feature
  5547    precedence examples</h3>
  5549   <div class=example>
  5550    <p>With the styles below, numbers are rendered proportionally when used
  5551     within a paragraph but are shown in tabular form within tables of prices:</p>
  5553    <pre>body {
  5554   font-variant-numeric: proportional-nums;
  5557 table.prices td {
  5558   font-variant-numeric: tabular-nums;
  5560 </pre>
  5561   </div>
  5563   <div class=example>
  5564    <p>When the <a href="#descdef-font-variant"
  5565     title="font-variant!!descriptor">font-variant</a> descriptor is used
  5566     within an <a href="#at-font-face-rule"><code>@font-face</code></a> rule,
  5567     it only applies to the font defined by that rule.</p>
  5569    <pre>@font-face {
  5570   font-family: MainText;
  5571   src: url(http://example.com/font.ttf);
  5572   font-variant: oldstyle-nums proportional-nums styleset(1,3);
  5575 body {
  5576   font-family: MainText, Helvetica;
  5579 table.prices td {
  5580   font-variant-numeric: tabular-nums;
  5582 </pre>
  5584    <p>In this case, old-style numerals will be used throughout but only where
  5585     the font "MainText" is used. Just as in the previous example, tabular
  5586     values will be used in price tables since ‘<a
  5587     href="#tabular-nums"><code class=property>tabular-nums</code></a>’
  5588     appears in a general style rule and its use is mutually exclusive with
  5589     ‘<a href="#proportional-nums"><code
  5590     class=property>proportional-nums</code></a>’. Stylistic alternate sets
  5591     will only be used where MainText is used.</p>
  5592   </div>
  5594   <div class=example>
  5595    <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule can
  5596     also be used to access font features in locally available fonts via the
  5597     use of <code>local()</code> in the ‘<a href="#descdef-src"><code
  5598     class=property>src</code></a>’ descriptor of the <a
  5599     href="#at-font-face-rule"><code>@font-face</code></a> definition:</p>
  5601    <pre>@font-face {
  5602   font-family: BodyText;
  5603   src: local("HiraMaruPro-W4");
  5604   font-variant: proportional-width;
  5605   font-feature-settings: "ital"; /* Latin italics within CJK text feature */
  5608 body { font-family: BodyText, serif; }
  5609 </pre>
  5611    <p>If available, a Japanese font "Hiragino Maru Gothic" will be used. When
  5612     text rendering occurs, Japanese kana will be proportionally spaced and
  5613     Latin text will be italicised. Text rendered with the fallback serif font
  5614     will use default rendering properties.</p>
  5615   </div>
  5617   <div class=example>
  5618    <p>In the example below, discretionary ligatures are enabled only for a
  5619     downloadable font but are disabled within spans of class "special":</p>
  5621    <pre>@font-face {
  5622   font-family: main;
  5623   src: url(fonts/ffmeta.woff) format("woff");
  5624   font-variant: discretionary-ligatures;
  5627 body         { font-family: main, Helvetica; }
  5628 span.special { font-variant-ligatures: no-discretionary-ligatures; }
  5629 </pre>
  5631    <p>Suppose one adds a rule using ‘<code
  5632     class=property>font-feature-settings</code>’ to enable discretionary
  5633     ligatures:</p>
  5635    <pre>body         { font-family: main, Helvetica; }
  5636 span         { font-feature-settings: "dlig"; }
  5637 span.special { font-variant-ligatures: no-discretionary-ligatures; }
  5638 </pre>
  5640    <p>In this case, discretionary ligatures <em>will</em> be rendered within
  5641     spans of class "special". This is because both the <a
  5642     href="#propdef-font-feature-settings"
  5643     title="font-feature-settings!!property">‘<code
  5644     class=property>font-feature-settings</code>’</a> and ‘<a
  5645     href="#propdef-font-variant-ligatures"><code
  5646     class=property>font-variant-ligatures</code></a>’ properties apply to
  5647     these spans. Although the ‘<code class=css>no-discretionary
  5648     ligatures</code>’ setting of ‘<a
  5649     href="#propdef-font-variant-ligatures"><code
  5650     class=property>font-variant-ligatures</code></a>’ effectively disables
  5651     the OpenType <span class=tag>dlig</span> feature, because the <a
  5652     href="#propdef-font-feature-settings"
  5653     title="font-feature-settings!!property">‘<code
  5654     class=property>font-feature-settings</code>’</a> is resolved after
  5655     that, the ‘<code class=property>dlig</code>’ value reenables
  5656     discretionary ligatures.</p>
  5657   </div>
  5659   <h2 id=object-model><span class=secno>8 </span>Object Model</h2>
  5661   <p>The contents of <a href="#at-font-face-rule"><code>@font-face</code></a>
  5662    and <a
  5663    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  5664    rules can be accessed via the following extensions to the CSS Object
  5665    Model.
  5667   <h3 id=om-fontface><span class=secno>8.1 </span>The <a
  5668    href="#cssfontfacerule"><code>CSSFontFaceRule</code></a> interface</h3>
  5670   <p>The <dfn id=cssfontfacerule>CSSFontFaceRule</dfn> interface represents a
  5671    <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
  5673   <pre class=idl>
  5674 interface CSSFontFaceRule : CSSRule {
  5675   attribute DOMString family;
  5676   attribute DOMString src;
  5677   attribute DOMString style;
  5678   attribute DOMString weight;
  5679   attribute DOMString stretch;
  5680   attribute DOMString unicodeRange;
  5681   attribute DOMString variant;
  5682   attribute DOMString featureSettings;
  5683 }</pre>
  5685   <p>The DOM Level 2 Style specification <a href="#DOM-LEVEL-2-STYLE"
  5686    rel=biblioentry>[DOM-LEVEL-2-STYLE]<!--{{DOM-LEVEL-2-STYLE}}--></a>
  5687    defined a different variant of this rule. This definition supercedes that
  5688    one.
  5690   <h3 id=om-fontfeaturevalues><span class=secno>8.2 </span>The <a
  5691    href="#cssfontfeaturevaluesrule"><code>CSSFontFeatureValuesRule</code></a>
  5692    interface</h3>
  5694   <p>The <code>CSSRule</code> interface is extended as follows:
  5696   <pre class=idl>partial interface CSSRule {
  5697   const unsigned short FONT_FEATURE_VALUES_RULE = 14;
  5698 }</pre>
  5700   <p>The <dfn id=cssfontfeaturevaluesrule>CSSFontFeatureValuesRule</dfn>
  5701    interface represents a <a
  5702    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  5703    rule.
  5705   <pre class=idl>interface CSSFontFeatureValuesRule : CSSRule {
  5706   readonly attribute DOMString familyList;
  5707   readonly attribute DOMString valueText;
  5708 };</pre>
  5710   <dl class=idl-attributes>
  5711    <dt><var>familyList</var> of type <code>DOMString</code>, readonly
  5713    <dd>The list of one or more font families for which a given set of feature
  5714     values is defined.
  5716    <dt><var>valueText</var> of type <code>DOMString</code>, readonly
  5718    <dd>Serialized set of feature values.
  5719   </dl>
  5721   <p class=issue>This needs to be reworked along the lines of <a
  5722    href="http://lists.w3.org/Archives/Public/www-style/2013May/0781.html">Tab's
  5723    proposal</a> for a rule containing a family list and map objects for each
  5724    of the feature types.
  5726   <h2 class=no-num id=platform-props-to-css>Appendix A: Mapping platform font
  5727    properties to CSS properties</h2>
  5729   <p><em>This appendix is included as background for some of the problems and
  5730    situations that are described in other sections. It should be viewed as
  5731    informative only.</em>
  5733   <p>Font properties in CSS are designed to be independent of the underlying
  5734    font formats used; they can be used to specify bitmap fonts, Type1 fonts,
  5735    SVG fonts in addition to the common TrueType and OpenType fonts. But there
  5736    are facets of the TrueType and OpenType formats that often cause confusion
  5737    for authors and present challenges to implementers on different platforms.
  5739   <p>Originally developed at Apple, TrueType was designed as an outline font
  5740    format for both screen and print. Microsoft joined Apple in developing the
  5741    TrueType format and both platforms have supported TrueType fonts since
  5742    then. Font data in the TrueType format consists of a set of tables
  5743    distinguished with common four-letter tag names, each containing a
  5744    specific type of data. For example, naming information, including
  5745    copyright and license information, is stored in the ‘<code
  5746    class=property>name</code>’ table. The <a
  5747    href="#character-map"><em>character map</em></a> (‘<code
  5748    class=property>cmap</code>’) table contains a mapping of character
  5749    encodings to glyphs. Apple later added additional tables for supporting
  5750    enhanced typographic functionality; these are now called Apple Advanced
  5751    Typography, or AAT, fonts. Microsoft and Adobe developed a separate set of
  5752    tables for advanced typography and called their format OpenType <a
  5753    href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>.
  5755   <p>In many cases the font data used under Microsoft Windows or Linux is
  5756    slightly different from the data used under Apple's Mac OS X because the
  5757    TrueType format allowed for explicit variation across platforms. This
  5758    includes font metrics, names and <a href="#character-map"><em>character
  5759    map</em></a> data.
  5761   <p>Specifically, font family name data is handled differently across
  5762    platforms. For TrueType and OpenType fonts these names are contained in
  5763    the ‘<code class=property>name</code>’ table, in name records with
  5764    name ID 1. Mulitple names can be stored for different locales, but
  5765    Microsoft recommends fonts always include at least a US English version of
  5766    the name. On Windows, Microsoft made the decision for backwards
  5767    compatibility to limit this family name to a maximum of four faces; for
  5768    larger groupings the "preferred family" (name ID 16) or "WWS family" (name
  5769    ID 21) can be used. Other platforms such as OSX don't have this
  5770    limitation, so the family name is used to define all possible groupings.
  5772   <p>Other name table data provides names used to uniquely identify a
  5773    specific face within a family. The full font name (name ID 4) and the
  5774    Postscript name (name ID 6) describe a single face uniquely. For example,
  5775    the bold face of the Gill Sans family has a fullname of "Gill Sans Bold"
  5776    and a Postscript name of "GillSans-Bold". There can be multiple localized
  5777    versions of the fullname for a given face, but the Postscript name is
  5778    always a unique name made from a limited set of ASCII characters.
  5780   <p>On various platforms, different names are used to search for a font. For
  5781    example, with the Windows GDI CreateIndirectFont API, either a family or
  5782    fullname can be used to lookup a face, while on Mac OS X the
  5783    CTFontCreateWithName API call is used to lookup a given face using the
  5784    fullname and Postscript name. Under Linux, the fontconfig API allows fonts
  5785    to be searched using any of these names. In situations where platform
  5786    API's automatically substitute other font choices, it may be necessary to
  5787    verify a returned font matches a given name.
  5789   <p>The weight of a given face can be determined via the usWeightClass field
  5790    of the OS/2 table or inferred from the style name (name ID 2). Likewise,
  5791    the width can be determined via the usWidthClass of the OS/2 table or
  5792    inferred from the style name. For historical reasons related to synthetic
  5793    bolding at weights 200 or lower with the Windows GDI API, font designers
  5794    have sometimes skewed values in the OS/2 table to avoid these weights.
  5796   <p>Rendering complex scripts that use contextual shaping such as Thai,
  5797    Arabic and Devanagari requires features present only in OpenType or AAT
  5798    fonts. Currently, complex script rendering is supported on Windows and
  5799    Linux using OpenType font features while both OpenType and AAT font
  5800    features are used under Mac OS X.
  5802   <h2 class=no-num id=ch-ch-ch-changes>Changes</h2>
  5804   <h3 class=no-num id=recent-changes> Changes from the <a
  5805    href="http://www.w3.org/TR/2013/WD-css3-fonts-20130212/">February 2013
  5806    CSS3 Fonts Working Draft</a></h3>
  5808   <p>Major changes include:
  5810   <ul>
  5811    <li>Moved font load events into a separate <a
  5812     href="http://dev.w3.org/csswg/css3-font-load-events/">spec</a>
  5814    <li>Tightened syntax rules for <a
  5815     href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  5816     rules
  5818    <li>Added grammar productions for <a
  5819     href="#at-font-face-rule"><code>@font-face</code></a> and <a
  5820     href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  5821     rules
  5823    <li>Tightened definition of synthetic oblique
  5825    <li>Revised definition of ‘<a href="#descdef-unicode-range"><code
  5826     class=property>unicode-range</code></a>’ descriptor
  5827   </ul>
  5829   <h2 class=no-num id=acknowledgments>Acknowledgments</h2>
  5831   <p>I'd like to thank Tal Leming, Jonathan Kew and Christopher Slye for all
  5832    their help and feedback. John Hudson was kind enough to take the time to
  5833    explain the subtleties of OpenType language tags and provided the example
  5834    of character variant usage for displaying text on Byzantine seals. Ken
  5835    Lunde and Eric Muller provided valuable feedback on CJK OpenType features
  5836    and Unicode variation selectors. The idea for supporting font features by
  5837    using <a href="#propdef-font-variant"
  5838    title="font-variant!!property">‘<code
  5839    class=property>font-variant</code>’</a> subproperties originated with
  5840    Håkon Wium Lie, Adam Twardoch and Tal Leming. Elika Etemad supplied some
  5841    of the initial design ideas for the <a
  5842    href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
  5843    rule. Thanks also to House Industries for allowing the use of Ed Interlock
  5844    in the discretionary ligatures example.
  5846   <p>A special thanks to Robert Bringhurst for the sublime mind expansion
  5847    that is <em>The Elements of Typographic Style</em>.
  5849   <h2 class=no-num id=conformance> Conformance</h2>
  5851   <h3 class=no-num id=conventions> Document Conventions</h3>
  5853   <p>Conformance requirements are expressed with a combination of descriptive
  5854    assertions and RFC 2119 terminology. The key words “MUST”, “MUST
  5855    NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”,
  5856    “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the
  5857    normative parts of this document are to be interpreted as described in RFC
  5858    2119. However, for readability, these words do not appear in all uppercase
  5859    letters in this specification.
  5861   <p>All of the text of this specification is normative except sections
  5862    explicitly marked as non-normative, examples, and notes. <a
  5863    href="#RFC2119" rel=biblioentry>[RFC2119]<!--{{!RFC2119}}--></a>
  5865   <p>Examples in this specification are introduced with the words “for
  5866    example” or are set apart from the normative text with
  5867    <code>class="example"</code>, like this:
  5869   <div class=example>
  5870    <p>This is an example of an informative example.
  5871   </div>
  5873   <p>Informative notes begin with the word “Note” and are set apart from
  5874    the normative text with <code>class="note"</code>, like this:
  5876   <p class=note>Note, this is an informative note.
  5878   <h3 class=no-num id=conformance-classes> Conformance Classes</h3>
  5880   <p>Conformance to CSS Fonts Level 3 Module is defined for three conformance
  5881    classes:
  5883   <dl>
  5884    <dt><dfn id=style-sheet title="style sheet!!as conformance class">style
  5885     sheet</dfn>
  5887    <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
  5888     style sheet</a>.
  5890    <dt><dfn id=renderer>renderer</dfn>
  5892    <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
  5893     that interprets the semantics of a style sheet and renders documents that
  5894     use them.
  5896    <dt><dfn id=authoring-tool>authoring tool</dfn>
  5898    <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
  5899     that writes a style sheet.
  5900   </dl>
  5902   <p>A style sheet is conformant to CSS Fonts Level 3 Module if all of its
  5903    declarations that use properties defined in this module have values that
  5904    are valid according to the generic CSS grammar and the individual grammars
  5905    of each property as given in this module.
  5907   <p>A renderer is conformant to CSS Fonts Level 3 Module if, in addition to
  5908    interpreting the style sheet as defined by the appropriate specifications,
  5909    it supports all the features defined by CSS Fonts Level 3 Module by
  5910    parsing them correctly and rendering the document accordingly. However,
  5911    the inability of a UA to correctly render a document due to limitations of
  5912    the device does not make the UA non-conformant. (For example, a UA is not
  5913    required to render color on a monochrome monitor.)
  5915   <p>An authoring tool is conformant to CSS Fonts Level 3 Module if it writes
  5916    style sheets that are syntactically correct according to the generic CSS
  5917    grammar and the individual grammars of each feature in this module, and
  5918    meet all other conformance requirements of style sheets as described in
  5919    this module.
  5921   <h3 class=no-num id=partial> Partial Implementations</h3>
  5923   <p>So that authors can exploit the forward-compatible parsing rules to
  5924    assign fallback values, CSS renderers <strong>must</strong> treat as
  5925    invalid (and <a
  5926    href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore as
  5927    appropriate</a>) any at-rules, properties, property values, keywords, and
  5928    other syntactic constructs for which they have no usable level of support.
  5929    In particular, user agents <strong>must not</strong> selectively ignore
  5930    unsupported component values and honor supported values in a single
  5931    multi-value property declaration: if any value is considered invalid (as
  5932    unsupported values must be), CSS requires that the entire declaration be
  5933    ignored.
  5935   <h3 class=no-num id=experimental> Experimental Implementations</h3>
  5937   <p>To avoid clashes with future CSS features, the CSS2.1 specification
  5938    reserves a <a
  5939    href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
  5940    syntax</a> for proprietary and experimental extensions to CSS.
  5942   <p>Prior to a specification reaching the Candidate Recommendation stage in
  5943    the W3C process, all implementations of a CSS feature are considered
  5944    experimental. The CSS Working Group recommends that implementations use a
  5945    vendor-prefixed syntax for such features, including those in W3C Working
  5946    Drafts. This avoids incompatibilities with future changes in the draft.
  5948   <h3 class=no-num id=testing> Non-Experimental Implementations</h3>
  5950   <p>Once a specification reaches the Candidate Recommendation stage,
  5951    non-experimental implementations are possible, and implementors should
  5952    release an unprefixed implementation of any CR-level feature they can
  5953    demonstrate to be correctly implemented according to spec.
  5955   <p>To establish and maintain the interoperability of CSS across
  5956    implementations, the CSS Working Group requests that non-experimental CSS
  5957    renderers submit an implementation report (and, if necessary, the
  5958    testcases used for that implementation report) to the W3C before releasing
  5959    an unprefixed implementation of any CSS features. Testcases submitted to
  5960    W3C are subject to review and correction by the CSS Working Group.
  5962   <p>Further information on submitting testcases and implementation reports
  5963    can be found from on the CSS Working Group's website at <a
  5964    href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
  5965    Questions should be directed to the <a
  5966    href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
  5967    mailing list.
  5969   <h2 class=no-num id=references>References</h2>
  5971   <h3 class=no-num id=normative-references>Normative References</h3>
  5972   <!--begin-normative-->
  5973   <!-- Sorted by label -->
  5975   <dl class=bibliography>
  5976    <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
  5977     <!---->
  5979    <dt id=CHARMOD>[CHARMOD]
  5981    <dd>Martin J. Dürst; et al. <a
  5982     href="http://www.w3.org/TR/2005/REC-charmod-20050215/"><cite>Character
  5983     Model for the World Wide Web 1.0: Fundamentals.</cite></a> 15 February
  5984     2005. W3C Recommendation. URL: <a
  5985     href="http://www.w3.org/TR/2005/REC-charmod-20050215/">http://www.w3.org/TR/2005/REC-charmod-20050215/</a>
  5986     </dd>
  5987    <!---->
  5989    <dt id=CORS>[CORS]
  5991    <dd>Anne van Kesteren. <a
  5992     href="http://www.w3.org/TR/2013/CR-cors-20130129/"><cite>Cross-Origin
  5993     Resource Sharing.</cite></a> 29 January 2013. W3C Candidate
  5994     Recommendation. (Work in progress.) URL: <a
  5995     href="http://www.w3.org/TR/2013/CR-cors-20130129/">http://www.w3.org/TR/2013/CR-cors-20130129/</a>
  5996     </dd>
  5997    <!---->
  5999    <dt id=CSS21>[CSS21]
  6001    <dd>Bert Bos; et al. <a
  6002     href="http://www.w3.org/TR/2011/REC-CSS2-20110607"><cite>Cascading Style
  6003     Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 7 June
  6004     2011. W3C Recommendation. URL: <a
  6005     href="http://www.w3.org/TR/2011/REC-CSS2-20110607">http://www.w3.org/TR/2011/REC-CSS2-20110607</a>
  6006     </dd>
  6007    <!---->
  6009    <dt id=CSS3VAL>[CSS3VAL]
  6011    <dd>Håkon Wium Lie; Tab Atkins; Elika J. Etemad. <a
  6012     href="http://www.w3.org/TR/2012/CR-css3-values-20120828/"><cite>CSS
  6013     Values and Units Module Level 3.</cite></a> 28 August 2012. W3C Candidate
  6014     Recommendation. (Work in progress.) URL: <a
  6015     href="http://www.w3.org/TR/2012/CR-css3-values-20120828/">http://www.w3.org/TR/2012/CR-css3-values-20120828/</a>
  6016     </dd>
  6017    <!---->
  6019    <dt id=HTML5>[HTML5]
  6021    <dd>Ian Hickson. <a
  6022     href="http://www.w3.org/TR/2012/CR-html5-20121217/"><cite>HTML5.</cite></a>
  6023     17 December 2012. W3C Candidate Recommendation. (Work in progress.) URL:
  6024     <a
  6025     href="http://www.w3.org/TR/2012/CR-html5-20121217/">http://www.w3.org/TR/2012/CR-html5-20121217/</a>
  6026     </dd>
  6027    <!---->
  6029    <dt id=OPEN-FONT-FORMAT>[OPEN-FONT-FORMAT]
  6031    <dd><a
  6032     href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip"><cite>Information
  6033     technology — Coding of audio-visual objects — Part 22: Open Font
  6034     Format.</cite></a> International Organization for Standardization.
  6035     ISO/IEC 14496-22:2009. URL: <a
  6036     href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip</a>
  6037     </dd>
  6038    <!---->
  6040    <dt id=OPENTYPE>[OPENTYPE]
  6042    <dd><a
  6043     href="http://www.microsoft.com/typography/otspec/default.htm"><cite>OpenType
  6044     specification.</cite></a> Microsoft. URL: <a
  6045     href="http://www.microsoft.com/typography/otspec/default.htm">http://www.microsoft.com/typography/otspec/default.htm</a>
  6046     </dd>
  6047    <!---->
  6049    <dt id=OPENTYPE-FEATURES>[OPENTYPE-FEATURES]
  6051    <dd><a
  6052     href="http://www.microsoft.com/typography/otspec/featurelist.htm"><cite>OpenType
  6053     feature registry.</cite></a> Microsoft. URL: <a
  6054     href="http://www.microsoft.com/typography/otspec/featurelist.htm">http://www.microsoft.com/typography/otspec/featurelist.htm</a>
  6055     </dd>
  6056    <!---->
  6058    <dt id=RFC2119>[RFC2119]
  6060    <dd>S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key
  6061     words for use in RFCs to Indicate Requirement Levels.</cite></a> Internet
  6062     RFC 2119. URL: <a
  6063     href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
  6064     </dd>
  6065    <!---->
  6067    <dt id=UAX15>[UAX15]
  6069    <dd>Mark Davis; Ken Whistler. <a
  6070     href="http://www.unicode.org/reports/tr15/"><cite>Unicode Normalization
  6071     Forms.</cite></a> 31 August 2012. Unicode Standard Annex #15. URL: <a
  6072     href="http://www.unicode.org/reports/tr15/">http://www.unicode.org/reports/tr15/</a>
  6073     </dd>
  6074    <!---->
  6076    <dt id=UAX29>[UAX29]
  6078    <dd>Mark Davis. <a
  6079     href="http://www.unicode.org/reports/tr29/"><cite>Unicode Text
  6080     Segmentation.</cite></a> 12 September 2012. Unicode Standard Annex #29.
  6081     URL: <a
  6082     href="http://www.unicode.org/reports/tr29/">http://www.unicode.org/reports/tr29/</a>
  6083     </dd>
  6084    <!---->
  6086    <dt id=UNICODE6>[UNICODE6]
  6088    <dd>The Unicode Consortium. <a
  6089     href="http://www.unicode.org/versions/Unicode6.2.0/"><cite>The Unicode
  6090     Standard, Version 6.2.0.</cite></a> Defined by: The Unicode Standard,
  6091     Version 6.2.0 URL: <a
  6092     href="http://www.unicode.org/versions/Unicode6.2.0/">http://www.unicode.org/versions/Unicode6.2.0/</a>
  6093     </dd>
  6094    <!---->
  6095   </dl>
  6096   <!--end-normative-->
  6097   <!--{{!CSS21}}-->
  6098   <!--{{!CSS3VAL}}-->
  6099   <!--{{!OPENTYPE}}-->
  6100   <!--{{!OPENTYPE-FEATURES}}-->
  6101   <!--{{!OPEN-FONT-FORMAT}}-->
  6102   <!--{{!UNICODE6}}-->
  6103   <!--{{!UAX15}}-->
  6104   <!--{{!UAX29}}-->
  6105   <!--{{!CORS}}-->
  6106   <!--{{!HTML5}}-->
  6107   <!--{{!CHARMOD}}-->
  6109   <h3 class=no-num id=other-references>Other References</h3>
  6110   <!--begin-informative-->
  6111   <!-- Sorted by label -->
  6113   <dl class=bibliography>
  6114    <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
  6115     <!---->
  6117    <dt id=AAT-FEATURES>[AAT-FEATURES]
  6119    <dd><a href="http://developer.apple.com/fonts/registry/"><cite>Apple
  6120     Advanced Typography font feature registry.</cite></a> Apple. URL: <a
  6121     href="http://developer.apple.com/fonts/registry/">http://developer.apple.com/fonts/registry/</a>
  6122     </dd>
  6123    <!---->
  6125    <dt id=ARABIC-TYPO>[ARABIC-TYPO]
  6127    <dd>Huda Smitshuijzen AbiFares. <cite>Arabic Typography: A Comprehensive
  6128     Sourcebook.</cite> Saqi Books. 2001. ISBN 0-86356-347-3.</dd>
  6129    <!---->
  6131    <dt id=CHARMOD-NORM>[CHARMOD-NORM]
  6133    <dd>François Yergeau; et al. <a
  6134     href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/"><cite>Character
  6135     Model for the World Wide Web 1.0: Normalization.</cite></a> 1 May 2012.
  6136     W3C Working Draft. (Work in progress.) URL: <a
  6137     href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/">http://www.w3.org/TR/2012/WD-charmod-norm-20120501/</a>
  6138     </dd>
  6139    <!---->
  6141    <dt id=CJKV-INFO-PROCESSING>[CJKV-INFO-PROCESSING]
  6143    <dd>Ken Lunde. <cite>CJKV Information Processing, Second Edition.</cite>
  6144     O'Reilly Media, Inc. 2009. ISBN 0-596-51447-1.</dd>
  6145    <!---->
  6147    <dt id=CSS3-CONDITIONAL>[CSS3-CONDITIONAL]
  6149    <dd>L. David Baron. <a
  6150     href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/"><cite>CSS
  6151     Conditional Rules Module Level 3.</cite></a> 13 December 2012. W3C
  6152     Working Draft. (Work in progress.) URL: <a
  6153     href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/">http://www.w3.org/TR/2012/WD-css3-conditional-20121213/</a>
  6154     </dd>
  6155    <!---->
  6157    <dt id=CSS3TEXT>[CSS3TEXT]
  6159    <dd>Elika J. Etemad; Koji Ishii. <a
  6160     href="http://www.w3.org/TR/2012/WD-css3-text-20121113/"><cite>CSS Text
  6161     Module Level 3.</cite></a> 13 November 2012. W3C Working Draft. (Work in
  6162     progress.) URL: <a
  6163     href="http://www.w3.org/TR/2012/WD-css3-text-20121113/">http://www.w3.org/TR/2012/WD-css3-text-20121113/</a>
  6164     </dd>
  6165    <!---->
  6167    <dt id=DIGITAL-TYPOGRAPHY>[DIGITAL-TYPOGRAPHY]
  6169    <dd>Richard Rubinstein. <cite>Digital Typography, An Introduction to Type
  6170     and Composition for Computer System Design.</cite> Addison-Wesley. 1988.
  6171     ISBN 0-201-17633-5.</dd>
  6172    <!---->
  6174    <dt id=DOM-LEVEL-2-STYLE>[DOM-LEVEL-2-STYLE]
  6176    <dd>Chris Wilson; Philippe Le Hégaret; Vidur Apparao. <a
  6177     href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/"><cite>Document
  6178     Object Model (DOM) Level 2 Style Specification.</cite></a> 13 November
  6179     2000. W3C Recommendation. URL: <a
  6180     href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/">http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/</a>
  6181     </dd>
  6182    <!---->
  6184    <dt id=ELEMTYPO>[ELEMTYPO]
  6186    <dd>Robert Bringhurst. <cite>The Elements of Typographic Style, Version
  6187     4.</cite> Hartley &amp; Marks. 2013. ISBN 0-88179-212-8.</dd>
  6188    <!---->
  6190    <dt id=LANGCULTTYPE>[LANGCULTTYPE]
  6192    <dd>John D. Berry, Ed. <cite>Language Culture Type.</cite> Graphis. 2001.
  6193     ISBN 1-932026-01-0.</dd>
  6194    <!---->
  6196    <dt id=OPENTYPE-FONT-GUIDE>[OPENTYPE-FONT-GUIDE]
  6198    <dd><a
  6199     href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf"><cite>OpenType
  6200     User Guide.</cite></a> FontShop International. URL: <a
  6201     href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf">https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf</a>
  6202     </dd>
  6203    <!---->
  6205    <dt id=RASTER-TRAGEDY>[RASTER-TRAGEDY]
  6207    <dd>Beat Stamm. <a href="http://www.rastertragedy.com/"><cite>The Raster
  6208     Tragedy at Low-Resolution Revisited.</cite></a> 7 December 2011. URL: <a
  6209     href="http://www.rastertragedy.com/">http://www.rastertragedy.com/</a></dd>
  6210    <!---->
  6212    <dt id=WINDOWS-GLYPH-PROC>[WINDOWS-GLYPH-PROC]
  6214    <dd>John Hudson. <a
  6215     href="http://www.microsoft.com/typography/developers/opentype/default.htm"><cite>Windows
  6216     Glyph Processing.</cite></a> Microsoft Typogrraphy. URL: <a
  6217     href="http://www.microsoft.com/typography/developers/opentype/default.htm">http://www.microsoft.com/typography/developers/opentype/default.htm</a>
  6218     </dd>
  6219    <!---->
  6220   </dl>
  6221   <!--end-informative-->
  6222   <!--{{ARABIC-TYPO}}-->
  6223   <!--{{CJKV-INFO-PROCESSING}}-->
  6224   <!--{{DIGITAL-TYPOGRAPHY}}-->
  6225   <!--{{DOM-LEVEL-2-STYLE}}-->
  6226   <!--{{ELEMTYPO}}-->
  6227   <!--{{LANGCULTTYPE}}-->
  6228   <!--{{OPENTYPE-FONT-GUIDE}}-->
  6229   <!--{{RASTER-TRAGEDY}}-->
  6230   <!--{{WINDOWS-GLYPH-PROC}}-->
  6231   <!--{{CHARMOD-NORM}}-->
  6232   <!--{{AAT-FEATURES}}-->
  6233   <!--{{CSS3-CONDITIONAL}}-->
  6234   <!--{{CSS3TEXT}}-->
  6236   <h2 class=no-num id=index>Index</h2>
  6237   <!--begin-index-->
  6239   <ul class=indexlist>
  6240    <li>100...900 weight values, <a href="#font-weight-numeric-values"
  6241     title="100...900 weight values"><strong>3.2</strong></a>
  6243    <li><var>&lt;absolute-size&gt;</var>, <a href="#absolute-size-value"
  6244     title="&lt;absolute-size&gt;"><strong>3.5</strong></a>
  6246    <li><var>&lt;common-lig-values&gt;</var>, <a href="#common-lig-values"
  6247     title="&lt;common-lig-values&gt;"><strong>6.4</strong></a>
  6249    <li><var>&lt;contextual-alt-values&gt;</var>, <a
  6250     href="#contextual-alt-values"
  6251     title="&lt;contextual-alt-values&gt;"><strong>6.4</strong></a>
  6253    <li><var>&lt;discretionary-lig-values&gt;</var>, <a
  6254     href="#discretionary-lig-values"
  6255     title="&lt;discretionary-lig-values&gt;"><strong>6.4</strong></a>
  6257    <li><var>&lt;east-asian-variant-values&gt;</var>, <a
  6258     href="#east-asian-variant-values"
  6259     title="&lt;east-asian-variant-values&gt;"><strong>6.10</strong></a>
  6261    <li><var>&lt;east-asian-width-values&gt;</var>, <a
  6262     href="#east-asian-width-values"
  6263     title="&lt;east-asian-width-values&gt;"><strong>6.10</strong></a>
  6265    <li><var>&lt;family-name&gt;</var>, <a href="#family-name-value"
  6266     title="&lt;family-name&gt;"><strong>3.1</strong></a>
  6268    <li><var>&lt;feature-tag-value&gt;</var>, <a href="#feature-tag-value"
  6269     title="&lt;feature-tag-value&gt;"><strong>6.12</strong></a>
  6271    <li><var>&lt;font-face-name&gt;</var>, <a href="#font-face-name-value"
  6272     title="&lt;font-face-name&gt;"><strong>4.3</strong></a>
  6274    <li><var>&lt;font-variant-css21&gt;</var>, <a
  6275     href="#font-variant-css21-values"
  6276     title="&lt;font-variant-css21&gt;"><strong>3.7</strong></a>
  6278    <li><var>&lt;generic-family&gt;</var>, <a href="#generic-family-value"
  6279     title="&lt;generic-family&gt;"><strong>3.1</strong></a>
  6281    <li><var>&lt;historical-lig-values&gt;</var>, <a
  6282     href="#historical-lig-values"
  6283     title="&lt;historical-lig-values&gt;"><strong>6.4</strong></a>
  6285    <li><var>&lt;length&gt;</var>, <a href="#length-size-value"
  6286     title="&lt;length&gt;"><strong>3.5</strong></a>
  6288    <li><var>&lt;number&gt;</var>, <a href="#aspect-ratio-value"
  6289     title="&lt;number&gt;"><strong>3.6</strong></a>
  6291    <li><var>&lt;numeric-figure-values&gt;</var>, <a
  6292     href="#numeric-figure-values"
  6293     title="&lt;numeric-figure-values&gt;"><strong>6.7</strong></a>
  6295    <li><var>&lt;numeric-fraction-values&gt;</var>, <a
  6296     href="#numeric-fraction-values"
  6297     title="&lt;numeric-fraction-values&gt;"><strong>6.7</strong></a>
  6299    <li><var>&lt;numeric-spacing-values&gt;</var>, <a
  6300     href="#numeric-spacing-values"
  6301     title="&lt;numeric-spacing-values&gt;"><strong>6.7</strong></a>
  6303    <li><var>&lt;percentage&gt;</var>, <a href="#percentage-size-value"
  6304     title="&lt;percentage&gt;"><strong>3.5</strong></a>
  6306    <li><var>&lt;relative-size&gt;</var>, <a href="#relative-size-value"
  6307     title="&lt;relative-size&gt;"><strong>3.5</strong></a>
  6309    <li><var>&lt;string&gt;</var>, <a
  6310     href="#font-language-override-string-value"
  6311     title="&lt;string&gt;"><strong>6.13</strong></a>
  6313    <li><var>&lt;urange&gt;</var>, <a href="#urange-value"
  6314     title="&lt;urange&gt;"><strong>4.5</strong></a>
  6316    <li><code>@font-face</code>, <a href="#at-font-face-rule"
  6317     title="@font-face"><strong>4.1</strong></a>
  6319    <li><code>@font-feature-values</code>, <a
  6320     href="#at-font-feature-values-rule"
  6321     title="@font-feature-values"><strong>6.9</strong></a>
  6323    <li>all-petite-caps, <a href="#all-petite-caps"
  6324     title=all-petite-caps><strong>6.6</strong></a>
  6326    <li>all-small-caps, <a href="#all-small-caps"
  6327     title=all-small-caps><strong>6.6</strong></a>
  6329    <li>annotation, <a href="#annotation"
  6330     title=annotation><strong>6.8</strong></a>
  6332    <li>aspect value, <a href="#aspect-value0" title="aspect
  6333     value"><strong>3.6</strong></a>
  6335    <li>authoring tool, <a href="#authoring-tool" title="authoring
  6336     tool"><strong>#</strong></a>
  6338    <li>auto
  6339     <ul>
  6340      <li>font-kerning, <a href="#font-kerning-auto-value" title="auto,
  6341       font-kerning"><strong>6.3</strong></a>
  6343      <li>font-size-adjust, <a href="#font-size-adjust-auto-value"
  6344       title="auto, font-size-adjust"><strong>3.6</strong></a>
  6345     </ul>
  6347    <li>bold, <a href="#bold" title=bold><strong>3.2</strong></a>
  6349    <li>bolder, <a href="#bolder" title=bolder><strong>3.2</strong></a>
  6351    <li>character map, <a href="#character-map" title="character
  6352     map"><strong>5.2</strong></a>
  6354    <li>character-variant, <a href="#character-variant"
  6355     title=character-variant><strong>6.8</strong></a>
  6357    <li>common-ligatures, <a href="#common-ligatures"
  6358     title=common-ligatures><strong>6.4</strong></a>
  6360    <li>condensed, <a href="#condensed"
  6361     title=condensed><strong>3.3</strong></a>
  6363    <li>contextual, <a href="#contextual"
  6364     title=contextual><strong>6.4</strong></a>
  6366    <li>CSSFontFaceRule, <a href="#cssfontfacerule"
  6367     title=CSSFontFaceRule><strong>8.1</strong></a>
  6369    <li>CSSFontFeatureValuesRule, <a href="#cssfontfeaturevaluesrule"
  6370     title=CSSFontFeatureValuesRule><strong>8.2</strong></a>
  6372    <li>cursive, definition of, <a href="#cursive0" title="cursive, definition
  6373     of"><strong>#</strong></a>
  6375    <li>default face, <a href="#default-face" title="default
  6376     face"><strong>5.2</strong></a>
  6378    <li>descriptor_declaration, <a href="#descriptordeclaration"
  6379     title="descriptor_declaration"><strong>4.1</strong></a>
  6381    <li>diagonal-fractions, <a href="#diagonal-fractions"
  6382     title=diagonal-fractions><strong>6.7</strong></a>
  6384    <li>discretionary-ligatures, <a href="#discretionary-ligatures"
  6385     title=discretionary-ligatures><strong>6.4</strong></a>
  6387    <li>expanded, <a href="#expanded" title=expanded><strong>3.3</strong></a>
  6389    <li>extra-condensed, <a href="#extra-condensed"
  6390     title=extra-condensed><strong>3.3</strong></a>
  6392    <li>extra-expanded, <a href="#extra-expanded"
  6393     title=extra-expanded><strong>3.3</strong></a>
  6395    <li>fantasy, definition of, <a href="#fantasy0" title="fantasy, definition
  6396     of"><strong>#</strong></a>
  6398    <li>feature_type, <a href="#featuretype"
  6399     title="feature_type"><strong>6.9.1</strong></a>
  6401    <li>feature_value_block, <a href="#featurevalueblock"
  6402     title="feature_value_block"><strong>6.9.1</strong></a>
  6404    <li>feature_value_definition, <a href="#featurevaluedefinition"
  6405     title="feature_value_definition"><strong>6.9.1</strong></a>
  6407    <li>font, <a href="#propdef-font" title=font><strong>3.7</strong></a>
  6409    <li>font specific, <a href="#font-specific" title="font
  6410     specific"><strong>6.8</strong></a>
  6412    <li>font-family
  6413     <ul>
  6414      <li>descriptor, <a href="#descdef-font-family" title="font-family,
  6415       descriptor"><strong>4.2</strong></a>
  6417      <li>property, <a href="#propdef-font-family" title="font-family,
  6418       property"><strong>3.1</strong></a>
  6419     </ul>
  6421    <li>font-feature-settings
  6422     <ul>
  6423      <li>descriptor, <a href="#descdef-font-feature-settings"
  6424       title="font-feature-settings, descriptor"><strong>4.7</strong></a>
  6426      <li>property, <a href="#propdef-font-feature-settings"
  6427       title="font-feature-settings, property"><strong>6.12</strong></a>
  6428     </ul>
  6430    <li>font-kerning, <a href="#propdef-font-kerning"
  6431     title=font-kerning><strong>6.3</strong></a>
  6433    <li>font-language-override, <a href="#propdef-font-language-override"
  6434     title=font-language-override><strong>6.13</strong></a>
  6436    <li>font-size, <a href="#propdef-font-size"
  6437     title=font-size><strong>3.5</strong></a>
  6439    <li>font-size-adjust, <a href="#propdef-font-size-adjust"
  6440     title=font-size-adjust><strong>3.6</strong></a>
  6442    <li>font-stretch
  6443     <ul>
  6444      <li>descriptor, <a href="#descdef-font-stretch" title="font-stretch,
  6445       descriptor"><strong>4.4</strong></a>
  6447      <li>property, <a href="#propdef-font-stretch" title="font-stretch,
  6448       property"><strong>3.3</strong></a>
  6449     </ul>
  6451    <li>font-style
  6452     <ul>
  6453      <li>descriptor, <a href="#descdef-font-style" title="font-style,
  6454       descriptor"><strong>4.4</strong></a>
  6456      <li>property, <a href="#propdef-font-style" title="font-style,
  6457       property"><strong>3.4</strong></a>
  6458     </ul>
  6460    <li>font-synthesis, <a href="#propdef-font-synthesis"
  6461     title=font-synthesis><strong>3.8</strong></a>
  6463    <li>font-variant
  6464     <ul>
  6465      <li>descriptor, <a href="#descdef-font-variant" title="font-variant,
  6466       descriptor"><strong>4.7</strong></a>
  6468      <li>property, <a href="#propdef-font-variant" title="font-variant,
  6469       property"><strong>6.11</strong></a>
  6470     </ul>
  6472    <li>font-variant-alternates, <a href="#propdef-font-variant-alternates"
  6473     title=font-variant-alternates><strong>6.8</strong></a>
  6475    <li>font-variant-caps, <a href="#propdef-font-variant-caps"
  6476     title=font-variant-caps><strong>6.6</strong></a>
  6478    <li>font-variant-east-asian, <a href="#propdef-font-variant-east-asian"
  6479     title=font-variant-east-asian><strong>6.10</strong></a>
  6481    <li>font-variant-ligatures, <a href="#propdef-font-variant-ligatures"
  6482     title=font-variant-ligatures><strong>6.4</strong></a>
  6484    <li>font-variant-numeric, <a href="#propdef-font-variant-numeric"
  6485     title=font-variant-numeric><strong>6.7</strong></a>
  6487    <li>font-variant-position, <a href="#propdef-font-variant-position"
  6488     title=font-variant-position><strong>6.5</strong></a>
  6490    <li>font-weight
  6491     <ul>
  6492      <li>descriptor, <a href="#descdef-font-weight" title="font-weight,
  6493       descriptor"><strong>4.4</strong></a>
  6495      <li>property, <a href="#propdef-font-weight" title="font-weight,
  6496       property"><strong>3.2</strong></a>
  6497     </ul>
  6499    <li>font_face_rule, <a href="#fontfacerule"
  6500     title="font_face_rule"><strong>4.1</strong></a>
  6502    <li>FONT_FACE_SYM, <a href="#fontfacesym"
  6503     title="FONT_FACE_SYM"><strong>4.1</strong></a>
  6505    <li>font_family_name, <a href="#fontfamilyname"
  6506     title="font_family_name"><strong>6.9.1</strong></a>
  6508    <li>font_family_name_list, <a href="#fontfamilynamelist"
  6509     title="font_family_name_list"><strong>6.9.1</strong></a>
  6511    <li>font_feature_values_rule, <a href="#fontfeaturevaluesrule"
  6512     title="font_feature_values_rule"><strong>6.9.1</strong></a>
  6514    <li>FONT_FEATURE_VALUES_SYM, <a href="#fontfeaturevaluessym"
  6515     title="FONT_FEATURE_VALUES_SYM"><strong>6.9.1</strong></a>
  6517    <li>full-width, <a href="#full-width"
  6518     title=full-width><strong>6.10</strong></a>
  6520    <li>historical-forms, <a href="#historical-forms"
  6521     title=historical-forms><strong>6.8</strong></a>
  6523    <li>historical-ligatures, <a href="#historical-ligatures"
  6524     title=historical-ligatures><strong>6.4</strong></a>
  6526    <li>italic, <a href="#italic" title=italic><strong>3.4</strong></a>
  6528    <li>jis04, <a href="#jis04" title=jis04><strong>6.10</strong></a>
  6530    <li>jis78, <a href="#jis78" title=jis78><strong>6.10</strong></a>
  6532    <li>jis83, <a href="#jis83" title=jis83><strong>6.10</strong></a>
  6534    <li>jis90, <a href="#jis90" title=jis90><strong>6.10</strong></a>
  6536    <li>lighter, <a href="#lighter" title=lighter><strong>3.2</strong></a>
  6538    <li>lining-nums, <a href="#lining-nums"
  6539     title=lining-nums><strong>6.7</strong></a>
  6541    <li>monospace, definition of, <a href="#monospace0" title="monospace,
  6542     definition of"><strong>#</strong></a>
  6544    <li>no-common-ligatures, <a href="#no-common-ligatures"
  6545     title=no-common-ligatures><strong>6.4</strong></a>
  6547    <li>no-contextual, <a href="#no-contextual"
  6548     title=no-contextual><strong>6.4</strong></a>
  6550    <li>no-discretionary-ligatures, <a href="#no-discretionary-ligatures"
  6551     title=no-discretionary-ligatures><strong>6.4</strong></a>
  6553    <li>no-historical-ligatures, <a href="#no-historical-ligatures"
  6554     title=no-historical-ligatures><strong>6.4</strong></a>
  6556    <li>none
  6557     <ul>
  6558      <li>font-kerning, <a href="#font-kerning-none-value" title="none,
  6559       font-kerning"><strong>6.3</strong></a>
  6561      <li>font-size-adjust, <a href="#font-size-adjust-none-value"
  6562       title="none, font-size-adjust"><strong>3.6</strong></a>
  6564      <li>font-variant, <a href="#font-variant-none-value" title="none,
  6565       font-variant"><strong>6.11</strong></a>
  6567      <li>font-variant-ligatures, <a href="#font-variant-ligatures-none-value"
  6568       title="none, font-variant-ligatures"><strong>6.4</strong></a>
  6569     </ul>
  6571    <li>normal
  6572     <ul>
  6573      <li>font-feature-settings, <a href="#font-feature-settings-normal-value"
  6574       title="normal, font-feature-settings"><strong>6.12</strong></a>
  6576      <li>font-kerning, <a href="#font-kerning-normal-value" title="normal,
  6577       font-kerning"><strong>6.3</strong></a>
  6579      <li>font-language-override, <a
  6580       href="#font-language-override-normal-value" title="normal,
  6581       font-language-override"><strong>6.13</strong></a>
  6583      <li>font-stretch, <a href="#font-stretch-normal-value" title="normal,
  6584       font-stretch"><strong>3.3</strong></a>
  6586      <li>font-style, <a href="#font-style-normal-value" title="normal,
  6587       font-style"><strong>3.4</strong></a>
  6589      <li>font-variant, <a href="#font-variant-normal-value" title="normal,
  6590       font-variant"><strong>6.11</strong></a>
  6592      <li>font-variant-alternates, <a
  6593       href="#font-variant-alternates-normal-value" title="normal,
  6594       font-variant-alternates"><strong>6.8</strong></a>
  6596      <li>font-variant-caps, <a href="#font-variant-caps-normal-value"
  6597       title="normal, font-variant-caps"><strong>6.6</strong></a>
  6599      <li>font-variant-east-asian, <a
  6600       href="#font-variant-east-asian-normal-value" title="normal,
  6601       font-variant-east-asian"><strong>6.10</strong></a>
  6603      <li>font-variant-ligatures, <a
  6604       href="#font-variant-ligatures-normal-value" title="normal,
  6605       font-variant-ligatures"><strong>6.4</strong></a>
  6607      <li>font-variant-numeric, <a href="#font-variant-numeric-normal-value"
  6608       title="normal, font-variant-numeric"><strong>6.7</strong></a>
  6610      <li>font-variant-position, <a href="#font-variant-position-normal-value"
  6611       title="normal, font-variant-position"><strong>6.5</strong></a>
  6613      <li>font-weight, <a href="#font-weight-normal-value" title="normal,
  6614       font-weight"><strong>3.2</strong></a>
  6615     </ul>
  6617    <li>oblique, <a href="#oblique" title=oblique><strong>3.4</strong></a>
  6619    <li>oldstyle-nums, <a href="#oldstyle-nums"
  6620     title=oldstyle-nums><strong>6.7</strong></a>
  6622    <li>ordinal, <a href="#ordinal" title=ordinal><strong>6.7</strong></a>
  6624    <li>ornaments, <a href="#ornaments"
  6625     title=ornaments><strong>6.8</strong></a>
  6627    <li>petite-caps, <a href="#petite-caps"
  6628     title=petite-caps><strong>6.6</strong></a>
  6630    <li>proportional-nums, <a href="#proportional-nums"
  6631     title=proportional-nums><strong>6.7</strong></a>
  6633    <li>proportional-width, <a href="#proportional-width"
  6634     title=proportional-width><strong>6.10</strong></a>
  6636    <li>renderer, <a href="#renderer" title=renderer><strong>#</strong></a>
  6638    <li>ruby, <a href="#ruby" title=ruby><strong>6.10</strong></a>
  6640    <li>sans-serif, definition of, <a href="#sans-serif0" title="sans-serif,
  6641     definition of"><strong>#</strong></a>
  6643    <li>semi-condensed, <a href="#semi-condensed-"
  6644     title=semi-condensed><strong>3.3</strong></a>
  6646    <li>semi-expanded, <a href="#semi-expanded"
  6647     title=semi-expanded><strong>3.3</strong></a>
  6649    <li>serif, definition of, <a href="#serif0" title="serif, definition
  6650     of"><strong>#</strong></a>
  6652    <li>simplified, <a href="#simplified"
  6653     title=simplified><strong>6.10</strong></a>
  6655    <li>slashed-zero, <a href="#slashed-zero"
  6656     title=slashed-zero><strong>6.7</strong></a>
  6658    <li>small-caps, <a href="#small-caps"
  6659     title=small-caps><strong>6.6</strong></a>
  6661    <li>src, <a href="#descdef-src" title=src><strong>4.3</strong></a>
  6663    <li>stacked-fractions, <a href="#stacked-fractions"
  6664     title=stacked-fractions><strong>6.7</strong></a>
  6666    <li>style sheet
  6667     <ul>
  6668      <li>as conformance class, <a href="#style-sheet" title="style sheet, as
  6669       conformance class"><strong>#</strong></a>
  6670     </ul>
  6672    <li>styleset, <a href="#styleset" title=styleset><strong>6.8</strong></a>
  6674    <li>stylistic, <a href="#stylistic"
  6675     title=stylistic><strong>6.8</strong></a>
  6677    <li>sub, <a href="#sub" title=sub><strong>6.5</strong></a>
  6679    <li>super, <a href="#super" title=super><strong>6.5</strong></a>
  6681    <li>swash, <a href="#swash" title=swash><strong>6.8</strong></a>
  6683    <li>system font fallback, <a href="#system-font-fallback" title="system
  6684     font fallback"><strong>5.2</strong></a>
  6686    <li>tabular-nums, <a href="#tabular-nums"
  6687     title=tabular-nums><strong>6.7</strong></a>
  6689    <li>titling-caps, <a href="#titling-caps"
  6690     title=titling-caps><strong>6.6</strong></a>
  6692    <li>traditional, <a href="#traditional"
  6693     title=traditional><strong>6.10</strong></a>
  6695    <li>ultra-condensed, <a href="#ultra-condensed"
  6696     title=ultra-condensed><strong>3.3</strong></a>
  6698    <li>ultra-expanded, <a href="#ultra-expanded"
  6699     title=ultra-expanded><strong>3.3</strong></a>
  6701    <li>unicase, <a href="#unicase" title=unicase><strong>6.6</strong></a>
  6703    <li>unicode-range, <a href="#descdef-unicode-range"
  6704     title=unicode-range><strong>4.5</strong></a>
  6706    <li>weight, <a href="#weight" title=weight><strong>2</strong></a>
  6708    <li>width, <a href="#width" title=width><strong>2</strong></a>
  6709   </ul>
  6710   <!--end-index-->
  6712   <h2 class=no-num id=property-index>Property index</h2>
  6713   <!--begin-properties-->
  6715   <table class=proptable>
  6716    <thead>
  6717     <tr>
  6718      <th>Property
  6720      <th>Values
  6722      <th>Initial
  6724      <th>Applies to
  6726      <th>Inh.
  6728      <th>Percentages
  6730      <th>Media
  6732    <tbody>
  6733     <tr>
  6734      <th><a class=property href="#propdef-font">font</a>
  6736      <td>[ [ &lt;‘font-style’&gt; || &lt;font-variant-css21&gt; ||
  6737       &lt;‘font-weight’&gt; || &lt;‘font-stretch’ ]?
  6738       &lt;‘font-size’&gt; [ / &lt;‘line-height’&gt; ]?
  6739       &lt;‘font-family’&gt; ] | caption | icon | menu | message-box |
  6740       small-caption | status-bar
  6742      <td>see individual properties
  6744      <td>all elements
  6746      <td>yes
  6748      <td>see individual properties
  6750      <td>visual
  6752     <tr>
  6753      <th><span class=property>font-family</span>
  6755      <td>[ &lt;family-name&gt; | &lt;generic-family&gt; ] #
  6757      <td>depends on user agent
  6759      <td>all elements
  6761      <td>yes
  6763      <td>N/A
  6765      <td>visual
  6767     <tr>
  6768      <th><span class=property>font-feature-settings</span>
  6770      <td>normal | &lt;feature-tag-value&gt; #
  6772      <td>normal
  6774      <td>all elements
  6776      <td>yes
  6778      <td>N/A
  6780      <td>visual
  6782     <tr>
  6783      <th><a class=property href="#propdef-font-kerning">font-kerning</a>
  6785      <td>auto | normal | none
  6787      <td>auto
  6789      <td>all elements
  6791      <td>yes
  6793      <td>N/A
  6795      <td>visual
  6797     <tr>
  6798      <th><a class=property
  6799       href="#propdef-font-language-override">font-language-override</a>
  6801      <td>normal | &lt;string&gt;
  6803      <td>normal
  6805      <td>all elements
  6807      <td>yes
  6809      <td>N/A
  6811      <td>visual
  6813     <tr>
  6814      <th><a class=property href="#propdef-font-size">font-size</a>
  6816      <td>&lt;absolute-size&gt; | &lt;relative-size&gt; | &lt;length&gt; |
  6817       &lt;percentage&gt;
  6819      <td>medium
  6821      <td>all elements
  6823      <td>yes
  6825      <td>refer to parent element's font size
  6827      <td>visual
  6829     <tr>
  6830      <th><a class=property
  6831       href="#propdef-font-size-adjust">font-size-adjust</a>
  6833      <td>none | auto | &lt;number&gt;
  6835      <td>none
  6837      <td>all elements
  6839      <td>yes
  6841      <td>N/A
  6843      <td>visual
  6845     <tr>
  6846      <th><span class=property>font-stretch</span>
  6848      <td>normal | ultra-condensed | extra-condensed | condensed |
  6849       semi-condensed | semi-expanded | expanded | extra-expanded |
  6850       ultra-expanded
  6852      <td>normal
  6854      <td>all elements
  6856      <td>yes
  6858      <td>N/A
  6860      <td>visual
  6862     <tr>
  6863      <th><span class=property>font-style</span>
  6865      <td>normal | italic | oblique
  6867      <td>normal
  6869      <td>all elements
  6871      <td>yes
  6873      <td>N/A
  6875      <td>visual
  6877     <tr>
  6878      <th><a class=property href="#propdef-font-synthesis">font-synthesis</a>
  6880      <td>none | [ weight || style ]
  6882      <td>weight style
  6884      <td>all elements
  6886      <td>yes
  6888      <td>N/A
  6890      <td>visual
  6892     <tr>
  6893      <th><span class=property>font-variant</span>
  6895      <td>normal | none | [ &lt;common-lig-values&gt; ||
  6896       &lt;discretionary-lig-values&gt; || &lt;historical-lig-values&gt; ||
  6897       &lt;contextual-alt-values&gt; || stylistic(&lt;feature-value-name&gt;)
  6898       || historical-forms || styleset(&lt;feature-value-name&gt; #) ||
  6899       character-variant(&lt;feature-value-name&gt; #) ||
  6900       swash(&lt;feature-value-name&gt;) ||
  6901       ornaments(&lt;feature-value-name&gt;) ||
  6902       annotation(&lt;feature-value-name&gt;) || [ small-caps | all-small-caps
  6903       | petite-caps | all-petite-caps | unicase | titling-caps ] ||
  6904       &lt;numeric-figure-values&gt; || &lt;numeric-spacing-values&gt; ||
  6905       &lt;numeric-fraction-values&gt; || ordinal || slashed-zero ||
  6906       &lt;east-asian-variant-values&gt; || &lt;east-asian-width-values&gt; ||
  6907       ruby ]
  6909      <td>normal
  6911      <td>all elements
  6913      <td>yes
  6915      <td>see individual properties
  6917      <td>visual
  6919     <tr>
  6920      <th><a class=property
  6921       href="#propdef-font-variant-alternates">font-variant-alternates</a>
  6923      <td>normal | [ stylistic(&lt;feature-value-name&gt;) || historical-forms
  6924       || styleset(&lt;feature-value-name&gt; #) ||
  6925       character-variant(&lt;feature-value-name&gt; #) ||
  6926       swash(&lt;feature-value-name&gt;) ||
  6927       ornaments(&lt;feature-value-name&gt;) ||
  6928       annotation(&lt;feature-value-name&gt;) ]
  6930      <td>normal
  6932      <td>all elements
  6934      <td>yes
  6936      <td>N/A
  6938      <td>visual
  6940     <tr>
  6941      <th><a class=property
  6942       href="#propdef-font-variant-caps">font-variant-caps</a>
  6944      <td>normal | small-caps | all-small-caps | petite-caps | all-petite-caps
  6945       | unicase | titling-caps
  6947      <td>normal
  6949      <td>all elements
  6951      <td>yes
  6953      <td>N/A
  6955      <td>visual
  6957     <tr>
  6958      <th><a class=property
  6959       href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
  6961      <td>normal | [ &lt;east-asian-variant-values&gt; ||
  6962       &lt;east-asian-width-values&gt; || ruby ]
  6964      <td>normal
  6966      <td>all elements
  6968      <td>yes
  6970      <td>N/A
  6972      <td>visual
  6974     <tr>
  6975      <th><a class=property
  6976       href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
  6978      <td>normal | none | [ &lt;common-lig-values&gt; ||
  6979       &lt;discretionary-lig-values&gt; || &lt;historical-lig-values&gt; ||
  6980       &lt;contextual-alt-values&gt; ]
  6982      <td>normal
  6984      <td>all elements
  6986      <td>yes
  6988      <td>N/A
  6990      <td>visual
  6992     <tr>
  6993      <th><a class=property
  6994       href="#propdef-font-variant-numeric">font-variant-numeric</a>
  6996      <td>normal | [ &lt;numeric-figure-values&gt; ||
  6997       &lt;numeric-spacing-values&gt; || &lt;numeric-fraction-values&gt; ||
  6998       ordinal || slashed-zero ]
  7000      <td>normal
  7002      <td>all elements
  7004      <td>yes
  7006      <td>N/A
  7008      <td>visual
  7010     <tr>
  7011      <th><a class=property
  7012       href="#propdef-font-variant-position">font-variant-position</a>
  7014      <td>normal | sub | super
  7016      <td>normal
  7018      <td>all elements
  7020      <td>yes
  7022      <td>N/A
  7024      <td>visual
  7026     <tr>
  7027      <th><span class=property>font-weight</span>
  7029      <td>normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600
  7030       | 700 | 800 | 900
  7032      <td>normal
  7034      <td>all elements
  7036      <td>yes
  7038      <td>N/A
  7040      <td>visual
  7041   </table>
  7042   <!--end-properties-->
  7043   <!--begin-descriptors-->
  7045   <table class=proptable>
  7046    <thead>
  7047     <tr>
  7048      <th>Descriptor
  7050      <th>Value
  7052      <th>Initial
  7054      <th>Percentages
  7056      <th>Media
  7058    <tbody>
  7059     <tr>
  7060      <th><span class=property>font-family</span>
  7062      <td>&lt;family-name&gt;
  7064      <td>N/A
  7066     <tr>
  7067      <th><span class=property>font-feature-settings</span>
  7069      <td>normal | &lt;feature-tag-value&gt; #
  7071      <td>normal
  7073     <tr>
  7074      <th><span class=property>font-stretch</span>
  7076      <td>normal | ultra-condensed | extra-condensed | condensed |
  7077       semi-condensed | semi-expanded | expanded | extra-expanded |
  7078       ultra-expanded
  7080      <td>normal
  7082     <tr>
  7083      <th><span class=property>font-style</span>
  7085      <td>normal | italic | oblique
  7087      <td>normal
  7089     <tr>
  7090      <th><span class=property>font-variant</span>
  7092      <td>normal | none | [ &lt;common-lig-values&gt; ||
  7093       &lt;discretionary-lig-values&gt; || &lt;historical-lig-values&gt; ||
  7094       &lt;contextual-alt-values&gt; || stylistic(&lt;feature-value-name&gt;)
  7095       || historical-forms || styleset(&lt;feature-value-name&gt; #) ||
  7096       character-variant(&lt;feature-value-name&gt; #) ||
  7097       swash(&lt;feature-value-name&gt;) ||
  7098       ornaments(&lt;feature-value-name&gt;) ||
  7099       annotation(&lt;feature-value-name&gt;) || [ small-caps | all-small-caps
  7100       | petite-caps | all-petite-caps | unicase | titling-caps ] ||
  7101       &lt;numeric-figure-values&gt; || &lt;numeric-spacing-values&gt; ||
  7102       &lt;numeric-fraction-values&gt; || ordinal || slashed-zero ||
  7103       &lt;east-asian-variant-values&gt; || &lt;east-asian-width-values&gt; ||
  7104       ruby ]
  7106      <td>normal
  7108     <tr>
  7109      <th><span class=property>font-weight</span>
  7111      <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
  7113      <td>normal
  7115     <tr>
  7116      <th><a class=property href="#descdef-src">src</a>
  7118      <td>[ &lt;url> [format(&lt;string> #)]? | &lt;font-face-name&gt; ] #
  7120      <td>N/A
  7122     <tr>
  7123      <th><a class=property href="#descdef-unicode-range">unicode-range</a>
  7125      <td>&lt;urange&gt; #
  7127      <td>U+0-10FFFF
  7128   </table>
  7129   <!--end-descriptors-->
  7130   <script type="text/javascript">
  7131 window.onload = function () {
  7132   if (!("devicePixelRatio" in window && window.devicePixelRatio > 1)) return;
  7133   var i, hiresElements = document.getElementsByClassName("hires");
  7134   for (i = 0; i < hiresElements.length; i++) {
  7135     var h = hiresElements[i];
  7136     if (h.tagName != "IMG") continue;
  7137     var src = h.getAttribute("src");
  7138     var src2x = src.replace(/\.\w+$/, function(m) { return "@2x" + m; });
  7139     h.src = src2x;
  7142 </script>
  7143 </html>
  7144 <!-- Keep this comment at the end of the file
  7145 Local variables:
  7146 mode: sgml
  7147 sgml-declaration:"~/SGML/HTML4.decl"
  7148 sgml-default-doctype-name:"html"
  7149 sgml-minimize-attributes:t
  7150 sgml-nofill-elements:("pre" "style" "br")
  7151 sgml-live-element-indicator:t
  7152 sgml-omittag:nil
  7153 sgml-shorttag:nil
  7154 sgml-namecase-general:t
  7155 sgml-general-insert-case:lower
  7156 sgml-always-quote-attributes:t
  7157 sgml-indent-step:nil
  7158 sgml-indent-data:t
  7159 sgml-parent-document:nil
  7160 sgml-exposed-tags:nil
  7161 sgml-local-catalogs:nil
  7162 sgml-local-ecat-files:nil
  7163 End:
  7164 -->
  7165 <!--
  7167 to do:
  7169 - wording of OpenType family name handling
  7170 - handling combining sequences in the font matching algorithm
  7171 - fix-up fi ligature example
  7173 -->

mercurial