drafts: css3-page/Overview.src.html@33f961bea4f4

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     4 <title>

     5 CSS Paged Media Module Level 3

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    50   .RFC2119

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    56   em em.RFC2119

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    81 <body class="h-entry">

    82 <div>

    83 <div class="head">

    84 <!--logo-->

    85 <h1 class="p-name">CSS Paged Media Module Level 3</h1>

    86 <h2 class="no-num no-toc" id="w3c-working">[LONGSTATUS] <span class="dt-updated"><span class="value-title" title="[CDATE]">[DATE]</span></span></h2>

    87 <dl>

    88   <dt>This version:</dt>    <dd><a class="u-url" href="http://dev.w3.org/csswg/css3-page/">http://dev.w3.org/csswg/css3-page/</a></dd>

    89     <!-- <dd><a class="u-url" href="[VERSION]">http://www.w3.org/TR/[YEAR]/WD-[SHORTNAME]-[CDATE]</a></dd> -->

    90   <dt>Latest version:</dt>    <dd><a href="http://www.w3.org/TR/css3-page">http://www.w3.org/TR/css3-page</a></dd>

    91   <dt>Previous version:</dt>    <dd><a rel="previous" href="http://www.w3.org/TR/2006/WD-css3-page-20061010/">http://www.w3.org/TR/2006/WD-css3-page-20061010/</a></dd>

    92   <dt>Issue Tracking:</dt>

    93     <dd><a rel="issues" href="http://www.w3.org/Style/CSS/Tracker/products/13">http://www.w3.org/Style/CSS/Tracker/products/13</a>

    94 <!-- or use the wiki:

    95     <dd><a rel="issues" href="http://wiki.csswg.org/spec/css3-page"

    96            >http://wiki.csswg.org/spec/css3-page</a></dd>

    97 -->

    98   <dt>Feedback:</dt>

    99     <dd><a href="mailto:www-style@w3.org?subject=%5B[SHORTNAME]%5D%20feedback"

   100          >www-style@w3.org</a>

   101          with subject line &ldquo;<kbd>[[SHORTNAME]]

   102          <var>&hellip; message topic &hellip;</var></kbd>&rdquo;

   103          (<a rel="discussion" href="http://lists.w3.org/Archives/Public/www-style/"

   104            >archives</a>)

   106   <dt>Editors:</dt>

   107     <dd class="p-author h-card vcard">

   108      <span class="p-name fn">Melinda Grant</span>,

   109      <span class="p-org org">Hewlett-Packard</span></dd>

   110     <dd class="p-author h-card vcard">

   111      <span class="p-name fn">H&aring;kon Wium Lie</span>,

   112      <span class="p-org org">Opera Software</span></dd>

   113     <dd class="p-author h-card vcard">

   114      <span class="p-name fn">Elika J. Etemad</span>,

   115      <span class="p-org org">Mozilla</span></dd>

   116     <dd class="p-author h-card vcard">

   117      <span class="p-name fn">Simon Sapin</span>,

   118      <span class="p-org org">Kozea</span></dd>

   119 </dl>

   121 <!--copyright-->

   123 </div>

   124 <hr title="Separator for header">

   126 <h2 class="no-num no-toc" id="abstract">Abstract</h2>

   128 <p>

   129   <span class="p-summary">

   130 This module describes the page model that partitions a flow into pages. It

   131 builds on the <a href="http://www.w3.org/TR/CSS21/box.html">Box model module</a> and introduces

   132 and defines the page model and paged media. It adds functionality for

   133 pagination, page margins, page size and orientation, headers and footers,

   134 widows and orphans, and image orientation. Finally it extends generated content

   135 to enable page numbering and running headers / footers.  </span>

   136 </p>

   138 <!-- "Status of this document" -->

   140 <h2 class="no-num no-toc" id="status">Status of this Document</h2>

   142 <!--status-->

   144 <p>This document contains the <abbr title="Cascading Style Sheets">CSS3</abbr>

   145 Paged Media Module W3C Last Call <a href="/2005/10/Process-20051014/tr.html#RecsWD">Working Draft</a> of [DATE]. The

   146 Last Call period ends on <span class="fudge">TBD</span>.</p>

   148 <p>Expected next revision to this document is another LCWD, due to the

   149 substantive changes to page-margin box sizing and other areas that are now

   150 specified with more precision.</p>

   152 <p>The <a href="lc2_issues.htm">Disposition of Comments</a>

   153 document contains the current issues list and responses to input received

   154 during this Last Call period.</p>

   156 <h2 class="no-num no-toc" id="contents">Table of Contents</h2><!--begin-toc-->

   157 <!--end-toc-->

   158 <!-- "Introduction" -->

   159 <h2 id="intro">Introduction</h2>

   161 <p>Paged media (e.g., paper, transparencies, photo album pages, pages

   162 displayed on computer screens as printed output simulations) differ from

   163 <a href="http://www.w3.org/TR/CSS2/media.html#continuous-media-group">continuous media</a>

   164 in that the content of the document is split into one or more discrete

   165 static display surfaces. To handle pages, CSS3 Paged Media describes how:</p>

   167 <ul>

   168   <li><a href="#page-breaks">page breaks</a> are created and avoided;</li>

   169   <li>the page properties such as size, orientation, margins, border, and

   170   padding are specified;</li>

   171   <li>headers and footers are established within the page margins;</li>

   172   <li>content such as page counters are placed in the headers and footers; and</li>

   173   <li>orphans and widows can be controlled.</li>

   174 </ul>

   176 <p>This module defines a <a href="#page-model">page model</a> that specifies how a

   177 document is formatted within a rectangular area, called the

   178 <a href="#page-box-page-rule">page box</a>, that has finite width and height.

   180 <p>Although CSS3 does not specify how user agents transfer page boxes to sheets,

   181 it does include certain mechanisms for telling user agents about the intended

   182 page sheet <a href="#page-size">size and orientation</a>. In the general case,

   183 CSS3 assumes that one page box will be transferred to one surface of similar

   184 size.</p>

   186 <p>All properties defined in this specification also accept the

   187 <a href="http://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>

   188 keyword as their value, but for readability it has not been listed explicitly.

   190 <h2 id="conformance">Conformance</h2>

   192 <p>All of the text in this specification is normative except sections

   193 explicitly marked as non-normative, examples, and notes. The keywords

   194 "<em class="RFC2119">MUST</em>", "<em class="RFC2119">SHALL</em>",

   195 "<em class="RFC2119">MUST NOT</em>", "<em class="RFC2119">SHALL NOT</em>",

   196 "<em class="RFC2119">REQUIRED</em>", "<em class="RFC2119">SHOULD</em>",

   197 "<em class="RFC2119">SHOULD NOT</em>", "<em class="RFC2119">RECOMMENDED</em>",

   198 "<em class="RFC2119">MAY</em>", and "<em class="RFC2119">OPTIONAL</em>" when

   199 used in this document are to be interpreted as described in <cite>RFC

   200 2119</cite> [[!RFC2119]]. However, for readability, these words do not appear

   201 in all uppercase letters in this specification.</p>

   203 <p>Examples in this specification are introduced with the words "for example"

   204   or are set apart from the normative text with <code>class="example"</code>,

   205   like this:

   207 <div class="example">

   208   <p>This is an example of an informative example.</p>

   209 </div>

   211 <p>Informative notes begin with the word "Note" and are set apart from the

   212   normative text with <code>class="note"</code>, like this:

   214 <p class="note">Note, this is an informative note.</p>

   216 <h2 id="page-terms">Page Terminology</h2>

   218 <p>The following terminology and accompanying diagrams help to describe the

   219 page model:</p>

   221 <dl>

   222   <dt id="page-sheet">Page sheet</dt>

   223   <dd><img src="PageSheet.png" style="float: right;" alt="The corner of a page sheet with the non-printable area at the edge and printable area inside it"

   224   height="148" width="194">The page sheet is one surface of the physical

   225   medium. The illustration to the right shows a representation of the upper-left

   226   corner of a page sheet.</dd>

   228   <dt id="printable-area">Printable and non-printable areas</dt>

   229   <dd>The non-printable area is the area of a page sheet that a physical device such

   230   as a printer is not capable of marking reliably, usually due to the printer's

   231   paper handling mechanism. This value is printer dependent and is usually a

   232   small region along each edge of the page sheet. The printable area is the area

   233   of page sheet that a printer <em>is</em> capable of marking reliably. The size

   234   of the printable area is the size of the page sheet reduced by the size of the

   235   non-printable area. A user agent may not know the dimensions of this area for a

   236   particular printing device; but when its dimensions are known, user agents

   237   <em class="RFC2119">MAY</em> adjust the formatting of the document so that

   238   content falls within the printable area. How this adjustment is accomplished is

   239   device dependent within the constraints expressed in the sections

   240   <a href="#renderingpages">Rendering page boxes that do not fit a page sheet</a> and

   241   <a href="#content-outside-box">Content outside the page box</a>.</dd>

   243   <dt id="page-orientation">Page Orientation</dt>

   244   <dd>The page orientation is defined by comparing the length of the edges of a

   245   <a href="#page-box">page box</a>. The page box is a rectangle with two

   246   perpendicular edges called the long edge and the short edge. The length of the

   247   long edge is always greater than or equal to the length of the short edge. When

   248   the page box is square, the two edges are of the same length and either can be

   249   used as the long edge with the other being the short edge. This specification

   250   defines page orientations of 'portrait' and 'landscape'.</dd>

   252   <dt id="portrait">Portrait Orientation</dt>

   253   <dd>A portrait page's height is greater than or equal to its width. Horizontal

   254   elements are parallel to the short edge and vertical elements to the long edge.</dd>

   256   <dt id="landscape">Landscape Orientation</dt>

   257   <dd>A landscape page's width is greater than or equal to its height. Horizontal

   258   elements are parallel to the long edge and vertical elements to the short edge.

   259   <span class="note">Note that CSS3 makes no distinction between landscape and

   260   reverse-landscape orientations. However, future versions of CSS may do so.

   261   UAs should consider, when formatting for duplexed printing, the binding edge,

   262   page progression, and ease of reading when choosing between landscape and

   263   reverse-landscape renderings.</span>

   264   </dd>

   266   <dt id="duplex-printing">Duplex Printing</dt>

   267   <dd>Duplex printing prints one page box per side of a page sheet and uses both

   268   sides of the page sheet. This module provides no ability to specify whether a

   269   document is duplex printed, but the concept of left and right pages is based on

   270   the assumption that the document is duplex printed, regardless of whether or

   271   not it actually is.</dd>

   273   <dt id="binding-edge">Binding Edge</dt>

   274   <dd>The binding edge is the edge of the page box that is toward the binding if the

   275   material is bound. The binding edge often has a larger margin than the opposite

   276   edge to provide for the space used by the binding. The binding edge can be any

   277   of the four edges. However, page sheets are customarily bound so that the

   278   binding edge of page boxes with portrait orientation is vertical. This module

   279   provides no method to specify the binding edge. In duplex printing, the binding

   280   edge is on opposite sides of the page box for the left and right pages.</dd>

   282   <dt id="facing-pages">Facing Pages</dt>

   283   <dd>Facing pages are two sequential pages such that when the document is duplex

   284   printed they are on separate sheets of paper. Typically, the earlier page will

   285   be the back side of one sheet and the later page will be the front side of

   286   another. They are usually laid out so that the binding edges of facing pages

   287   are vertical and adjacent when the pages are placed in their normal reading

   288   orientation.</dd>

   290   <dt id="left-page">Left Page</dt>

   291   <dd>A page that would be on the left if it is part of a pair of facing pages as

   292   typically laid out. Page layouts for documents using a left-to-right page

   293   progression have the earlier of the facing pages on the left. Rules specific to

   294   the left page can be specified using the <span class="css">':left'</span>

   295   <i>page selector</i>.

   296   </dd>

   298   <dt id="right-page">Right Page</dt>

   299   <dd>A page that would be on the right if it is part of a pair of facing pages as

   300   typically laid out. Page layouts for documents using a right-to-left page

   301   progression have the earlier of the facing pages on the right. Rules specific

   302   to the right page can be specified using the <span class="css">':right'</span>

   303   <i>page selector</i>.

   304   </dd>

   305 </dl>

   308 <h2 id="page-box-page-rule">The Page Model</h2>

   310 <p>In the paged media formatting model, the document is transferred into one

   311 or more page boxes. The <dfn id="page-box">page box</dfn> is a specialized CSS

   312 box that maps to a rectangular print media surface, such as a page of paper.

   313 It is roughly analogous to the <a href="http://www.w3.org/TR/CSS21/visuren.html#viewport">viewport</a>.

   314 <img src="PageBox.png" style="float: right;" alt="" height="266" width="267">

   316 <p>As with other CSS <a href="http://www.w3.org/TR/CSS21/box.html">boxes</a>, a page box

   317 consists of margin, border, padding, and content areas. The content and

   318 margin areas of a page box have special functions:</p>

   320 <ul>

   321   <li>The content area of a page box is called the <dfn id="page-area">page

   322   area</dfn>. The content of the document is flowed into one or more page boxes.

   323   The page area acts as a container for all the boxes generated by the root

   324   element and its descendants that are laid out within a given page box. The

   325   edges of the page area on the first page establish the rectangle that is the

   326   initial <a href="http://www.w3.org/TR/CSS21/visudet.html#containing-block-details">containing block</a>

   327   of the document.</li>

   328   <li>The margin area of a page box is divided into

   329   16 <dfn>page-margin boxes</dfn>.

   330   Each page-margin box has its own margin, border, padding and content areas.

   331   Page-margin boxes are typically used to display running headers and footers.</li>

   332 </ul>

   334 <p>The properties of a <i>page box</i> are determined by properties

   335 <a href="http://www.w3.org/TR/CSS21/syndata.html#declaration">declared</a> within the

   336 <i>page context</i>, which is the

   337 <a href="http://www.w3.org/TR/CSS21/syndata.html#x14">declaration block</a> of the

   338 <code>@page</code> rule. Similarly the properties of a <i>page-margin box</i>

   339 are determined by properties declared within its <i>margin context</i>.

   340 Declarations in the page context can affect the page box and/or inherit

   341 to the page-margin boxes, but they do not apply to or inherit into the

   342 document's root element or other content.</p>

   344 <p>The <i>containing block</i> of the page box is specified using the 'size'

   345 property in the <i>page context</i>. The width and horizontal margins

   346 of the page box are then calculated exactly as for a

   347 <a href="http://www.w3.org/TR/CSS21/visudet.html#blockwidth">non-replaced

   348 block element in normal flow</a>. [[!CSS21]] The height and vertical margins

   349 of the page box are calculated analogously (instead of using the block height

   350 formulas). In both cases if the values are over-constrained, instead of

   351 ignoring any margins, the containing block is resized to coincide with the

   352 margin edges of the page box.

   354 <h3 id="painting">

   355 Page Backgrounds and Painting Order</h3>

   357   <p>When drawing a page of content, the page layers are painted in the

   358   following painting order (bottommost first):

   360   <ol>

   361     <li>page background

   362     <li>document canvas

   363     <li>page borders

   364     <li>document contents

   365     <li>page-margin boxes

   366   </ol>

   368   <p>In the page model, the page background behaves similar to the root background:

   369   its <a href="http://www.w3.org/TR/css3-background/#background-painting-area"><i>background painting area</i></a>

   370   is the entire page box, including its margins (regardless of 'background-clip').

   371   Page backgrounds are anchored within the page box's padding area by default

   372   (and honor 'background-origin' if the UA supports [[!CSS3BG]]).

   373   However if 'background-attachment' is ''fixed''

   374   then the image is positioned relative to the page box including its margins

   375   (i.e. the <a href="http://www.w3.org/TR/css3-background/#background-positioning-area"><i>background positioning area</i></a>,

   376   like the <i>background painting area</i>, is the page's margin box).

   378   <p>The document canvas background is drawn as the page box's background:

   379   by default its <i>background painting area</i> covers the page box's border box,

   380   and for UAs that support [[!CSS3BG]], follows the 'background-clip' value specified on the root element.

   381   It remains, however, positioned with respect to the root element

   382   or page area as usual.

   384   <p>The UA may support the <code>z-index</code> property for page-margin boxes.

   385   With respect to the page-margin boxes,

   386   the document canvas, page borders, and all of the document contents

   387   are treated as a single element with a <code>z-index</code> value of '0':

   388   the page-margin boxes never interleave with parts of the document content

   389   or between the content and the canvas.

   390   They may only paint in front of the document content or behind the document canvas.

   391   The page background is always painted underneath everything else.

   392   Since the <code>position</code> property does not apply to page-margin boxes,

   393   <code>z-index</code> always affects page-margin boxes

   394   as if they were positioned elements

   395   regardless of the <code>position</code> property's value.

   397   <p>The default painting order,

   398   or <a href="http://www.w3.org/TR/CSS21/zindex.html">CSS2.1 Appendix E</a> "tree order",

   399   of page-margin boxes with respect to each other is not specified.

   400   However, the page-margin boxes are defined to come

   401   after the page box and its contents.

   402   <span class="issue">Suggestions here are welcome.</span>

   404 <h3 id="content-outside-box">Content outside the page box</h3>

   406 <p>When formatting content in the page model, some content may end up outside the

   407 page box. For example, an element whose 'white-space' property has the value

   408 'pre' can generate a box that is wider than the page box. As another example,

   409 when boxes are positioned absolutely or relatively, they may end up in

   410 "inconvenient" locations. For example, images may be placed on the edge of

   411 the page box or 100,000 meters below the page box. </p>

   413 <p>A specification for the exact formatting of such elements lies outside the

   414 scope of this document. However, it is recommended that authors and user agents

   415 observe the following general principles concerning content outside the page

   416 box:</p>

   418 <ul>

   419   <li><p>Content should be allowed slightly beyond the page box to allow pages

   420   to "bleed".

   421   <li><p>User agents <em class="RFC2119">SHOULD</em> avoid generating a large

   422   number of content-empty pages to honor the positioning of elements (e.g.,

   423   printing 100 blank pages is probably neither the author's nor the user's

   424   intent).

   425   A <dfn id="content-empty">Content-empty page</dfn> is a page box whose page

   426   area contains no printable content other than backgrounds and/or borders. A

   427   page box whose page area contains generated content, or content whose

   428   visibility is 'hidden', or invisible content such as a zero-width space is

   429   not a content-empty page. On the other hand, a page containing only a

   430   background and/or borders and/or page-margin box content <em>is</em> a

   431   content-empty page.

   432   <p class="note">Note, however, that generating a small number of empty page

   433   boxes is sometimes necessary to honor the <span class="css">'left'</span> and

   434   <span class="css">'right'</span> values for <span class="property">'break-before'</span>

   435   and <span class="property">'break-after'</span>.</li>

   437   <li><p>Authors <em class="RFC2119">SHOULD NOT</em> position elements in

   438   inconvenient locations just to avoid rendering them. Instead:

   439   <ul>

   440     <li>To suppress box generation entirely, set the <span class="property">'display'</span> property to <span class="css">'none'</span>.</li>

   441     <li>To make a box invisible, set the <span class="property">'visibility'</span>

   442     property.</li>

   443     </ul></li>

   444     <li><p>This specification does not define how boxes positioned outside the page

   445     box are handled. Possibilities include discarding them or creating page boxes

   446     for them at the end of the document.</li>

   447 </ul>

   449 <h3 id="progression">Page Progression</h3>

   451 <p>CSS distinguishes between left pages and right pages on all documents,

   452 whether they are printed duplex or not. Each left page is followed by a

   453 right page and vice versa. Left and right pages can be styled differently

   454 with the <a href="#left-right-first"><code>:left</code> and <code>:right</code>

   455 pseudo-classes</a>.

   457 <p>Whether the first page of a document is a left page or a right page

   458 depends on the page progression of the document. The <dfn>page progression</dfn>

   459 is the direction in which the printed pages of a document would be sequenced

   460 when laid out side-to-side. For example, English and horizontally-set Japanese

   461 typically progress from left to right, whereas Arabic and vertically-set

   462 Japanese pages typically progress from right to left. In documents with

   463 a left-to-right page progression the first page of the document is a right

   464 page, and vice versa.</p>

   466 <p>The page progression direction is determined as follows:</p>

   468 <ul>

   469   <li>If text is laid out in horizontal lines, the page progression is the

   470   same as the inline progression.</li>

   471   <li>If text is laid out in vertical lines, the page progression is the

   472   same as the block progression.</li>

   473 </ul>

   475 <p>If the UA supports the 'direction' and 'writing-mode' properties

   476 from the CSS 3 Writing Modes Module [[CSS3-WRITING-MODES]], it must

   477 <a href="http://www.w3.org/TR/css3-writing-modes/#page-direction">determine</a>

   478 whether the first page is a left or right page from the values of those

   479 properties on the root element.</p>

   481 <p>

   482   To explicitly force a document to begin printing on a left or right page,

   483   authors can specify a <a href="http://www.w3.org/TR/css3-break/#break-before">'break-before'</a> value

   484   that that propagates a page break to the root. [[!CSS3-BREAK]]

   485   The UA must suppress the first (empty) page(s) in this case

   486   (and the <code>:first</code> pseudo-class matches the first printed page).

   488 <div class="example">

   489 <pre>

   490 html { break-before: always }

   491 </pre>

   493 <p>

   494   For an HTML document with a left-to-right page progression,

   495   the above style rule will cause the first page of the document

   496   to print on a ':left' page

   497 </p>

   499 <pre>

   500 html { break-before: left }

   501 </pre>

   503 <p>

   504   For an HTML document,

   505   the above style rule will cause the first page of the document

   506   to print on a ':left' page,

   507   regardless of the page progression.

   508 </p>

   509 </div>

   511 <h2 id="page-selector-and-context">Page Selectors and the Page Context</h2>

   513 <h3 id="at-page-rule">The @page Rule</h3>

   515 <p>Authors can specify various aspects of a page box, such as its dimensions,

   516 orientation, and margins, within an <span class="css">@page</span> rule.

   517 ''@page'' rules are allowed at the top-level of a stylesheet,

   518 as well as wherever

   519 <a href="http://www.w3.org/TR/CSS21/syndata.html#rule-sets">rule-sets</a>

   520 are allowed.

   521 An <span class="css">@page</span> rule consists of

   522 the keyword <span class="css">'@page'</span>,

   523 an <em class="RFC2119">OPTIONAL</em> comma-separated list of

   524 <a href="#page-selectors">page selectors</a>

   525 and a block of declarations

   526 (said to be in the <dfn id="page-context">page context</dfn>).

   527 An ''@page'' rule can also contain other at-rules,

   528 interleaved between declarations.

   529 The current level of this specification

   530 only allows <a href="#margin-at-rules">margin at-rules</a> inside ''@page''.

   532 <p>''@page'' rules without a selector list

   533   are considered to have a single, empty selector.

   534   ''@page'' rules apply to pages that <i>match</i>

   535   at least one of their selectors.

   537 <p>Properties declared within the page context apply to the page box.

   539 <p>If an error is encountered during the processing of a declaration block within

   540 a page or a margin context, the <a href="http://www.w3.org/TR/CSS21/syndata.html#parsing-errors">Rules for handling parsing errors</a>

   541 apply; that is, valid declarations within the block are applied.</p>

   544 <h3 id="page-selectors">Page selectors</h3>

   546 <p>A <dfn id="page-selector">page selector</dfn> is either:

   548 <ul>

   549   <li>one or more

   550     <a href="http://www.w3.org/TR/CSS21/syndata.html#characters">ASCII case-insensitive</a>

   551     <a href="#pseudo-classes">pseudo-classes</a>,

   552   <li>a <a href="#using-named-pages">page type</a>

   553     (a case-sensitive identifier)

   554     followed by zero or more pseudo-classes.

   555 </ul>

   557 <p>

   558   No whitespace is allowed between components of a selector.

   559   The <i title="page_selector">page selector grammar</i>

   560   and examples can be found below.

   562 <p>A selector is said to <dfn>match</dfn> a given page if and only if

   563   all of its components match the page.

   564   Empty selectors (ie. ''@page'' rules without a selector) match every page.

   565   <span class="note">Empty selectors have the weakest <i>specificity</i>.</span>

   567 <p><a href="#using-named-pages">Page type</a> selectors <i>match</i>

   568   pages of the named type generated by the 'page' property.

   569   <span id="page-selector-syntax-restrict">

   570     A page type name of ''auto''

   571     (<a href="http://www.w3.org/TR/CSS21/syndata.html#characters">ASCII case-insensitive</a>)

   572     does not make the rule invalid,

   573     but <em class="RFC2119">MUST</em> never match.

   574   </span>

   575   Individual <a href="#pseudo-classes">pseudo-classes</a> are defined below.

   577 <h4 id="pseudo-classes">

   578   <a id="left-right-first"></a>

   579   Page pseudo-classes: :left, :right, :first, and :blank

   580 </h4>

   582 <p>

   583   When printing double-sided documents,

   584   left and right pages are often formatted differently.

   585   This can be expressed through CSS pseudo-classes defined

   586   in the <a href="#page-context">page context</a>.

   588 <p>

   589   All pages are automatically classified by user agents

   590   as either left pages or right pages,

   591   based on <a href="#progression">page progression</a>.

   592   The '':left'' and '':right'' pseudo-classes only <i>match</i>

   593   left or right pages, respectively.

   595 <div class="example">

   596 The following example creates left and right binding edges using these pseudo-classes:

   597 <pre>

   598 @page :left {

   599 margin-left: 3cm;

   600 margin-right: 4cm;

   601 }

   603 @page :right {

   604 margin-left: 4cm;

   605 margin-right: 3cm;

   606 }

   607 </pre>

   608 </div>

   610 <p>If different declarations have been given for left and right pages, the user

   611 agent <em class="RFC2119">MUST</em> honor these declarations even if the user

   612 agent does not transfer the page boxes to left and right sheets (i.e., a

   613 printer that only prints on one side of the medium must nevertheless produce

   614 correctly formatted output).</p>

   616 <div class="note">

   617 <p>

   618   <em><strong>Note.</strong>

   619   Adding declarations to the <span class="css">':left'</span> or

   620   <span class="css">':right'</span> pseudo-class

   621   does not necessarily influence whether the document

   622   comes out of the printer double- or single-sided

   623   (which is outside the scope of this specification).</em>

   624 </p>

   625 </div>

   627 <p>

   628   The '':first'' pseudo-class only <i title="match">matches</i>

   629   the first printed page of a document.

   631 <div class="example">

   632 <pre>

   633 @page { margin: 2cm } /* All margins set to 2cm */

   635 @page :first {

   636 margin-top: 10cm /* Top margin on first page 10cm */

   637 }

   638 </pre>

   639 </div>

   641 <p>

   642   The '':blank'' pseudo-class only <i title="match">matches</i>

   643   <i title="content-empty page">content-empty pages</i>

   644   that appear as a result of

   645   <a href="http://www.w3.org/TR/css3-break/#forced-breaks">forced page breaks</a>.

   647 <div class="note">

   648   <p>Only the ''left'', ''right'', ''recto'' and ''verso'' values

   649     of the 'break-before' and 'break-after' properties

   650     can generate pages that match '':blank''.

   651 </div>

   653 <div class="example">

   654 <p>In this example, forced page break may occur before <code>h1</code> elements.

   655 <pre>

   656 h1 { break-before: left }

   658 @page :blank {

   659   @top-center { content: "This page is intentionally left blank" }

   660 }

   661 </pre>

   662 </div>

   664 <p>

   665   A page matched by '':blank'' can also be matched

   666   by other page pseudo-classes.

   668 <div class="example">

   670 <p>If headers have been specified on all right pages, a blank right

   671 page will be matched by both <code>:blank</code>

   672 and <code>:right</code>. Therefore, margin boxes set on right pages

   673 will have to be removed unless they are wanted on blank pages. Here is

   674 an example where the top center header is removed from blank pages,

   675 while the page number remains:

   677 <pre>

   678 h1 { break-before: left }

   680 @page :blank {

   681   @top-center { content: none }

   682 }

   684 @page :right {

   685   @top-center { content: "Preliminary edition" }

   686   @bottom-center { content: counter(page) }

   687 }

   688 </pre>

   690 <p>Due to the higher <i>specificity</i> of <code>:blank</code>

   691 over <code>:right</code>, the top center header is removed even

   692 if <code>content: none</code> comes before <code>content: "Preliminary

   693 edition"</code>.

   695 </div>

   697 <div class="note">

   698 <p><em><strong>Note.</strong> Future versions of CSS may include other page

   699 pseudo-classes.</em></p>

   700 </div>

   702 <h3 id="syntax-page-selector">@page rule grammar</h3>

   704 <p>The syntax for the @page rule is a specialization of the generic at-rule

   705 defined by CSS 2.1. This grammar extends the at-rule syntax to allow @page rules

   706 nested inside @media rules. User agents <em class="RFC2119">MUST</em> adhere

   707 to the following grammar:</p>

   709 <p>See [[!CSS21]], Section 4.1.1 and Appendix G for the expansion of missing

   710 productions:</p>

   711 <p id="specializatons-of-ATKEYWORD">

   712 All new lexical tokens are specializations of the ATKEYWORD lexical token:</p>

   713 <pre class="lexical">

   714 PAGE_SYM              ::= "@page"

   715 TOPLEFTCORNER_SYM     ::= "@top-left-corner"

   716 TOPLEFT_SYM           ::= "@top-left"

   717 TOPCENTER_SYM         ::= "@top-center"

   718 TOPRIGHT_SYM          ::= "@top-right"

   719 TOPRIGHTCORNER_SYM    ::= "@top-right-corner"

   720 BOTTOMLEFTCORNER_SYM  ::= "@bottom-left-corner"

   721 BOTTOMLEFT_SYM        ::= "@bottom-left"

   722 BOTTOMCENTER_SYM      ::= "@bottom-center"

   723 BOTTOMRIGHT_SYM       ::= "@bottom-right"

   724 BOTTOMRIGHTCORNER_SYM ::= "@bottom-right-corner"

   725 LEFTTOP_SYM           ::= "@left-top"

   726 LEFTMIDDLE_SYM        ::= "@left-middle"

   727 LEFTBOTTOM_SYM        ::= "@left-bottom"

   728 RIGHTTOP_SYM          ::= "@right-top"

   729 RIGHTMIDDLE_SYM       ::= "@right-middle"

   730 RIGHTBOTTOM_SYM       ::= "@right-bottom"

   732 <dfn>media</dfn> :

   733      MEDIA_SYM S* medium [ COMMA S* medium ]* LBRACE S* [ <i>page_rule</i> | ruleset ]* '}' S*

   734      ;

   736 <dfn id="syntax-prod-page">page_rule</dfn> :

   737      PAGE_SYM S* <i>page_selector_list</i> '{' S* <i>page_body</i> '}' S*

   738      ;

   740 <dfn>page_selector_list</dfn> :

   741      [ <i>page_selector</i> S* [ ',' <i>page_selector</i> S* ]* ]?

   742      ;

   744 <dfn>page_selector</dfn> :

   745      <i>pseudo_page</i>+ | IDENT <i>pseudo_page</i>*

   746      ;

   748 <dfn id="syntax-prod-pseudo-page">pseudo_page</dfn> :

   749      ':' [ "left" | "right" | "first" | "blank" ]

   750      ;

   752 <dfn>page_body</dfn> :  /* Can be empty */

   753      declaration? [ ';' S* <i>page_body</i> ]? |

   754      <i>page_margin_box</i> <i>page_body</i>

   755      ;

   757 <dfn id="syntax-prod-margin">page_margin_box</dfn> :

   758      <i>margin_sym</i> S* '{' S* declaration? [ ';' S* declaration? ]* '}' S*

   759      ;

   761 <dfn id="syntax-prod-margin-sym">margin_sym</dfn> :

   762      TOPLEFTCORNER_SYM |

   763      TOPLEFT_SYM |

   764      TOPCENTER_SYM |

   765      TOPRIGHT_SYM |

   766      TOPRIGHTCORNER_SYM |

   767      BOTTOMLEFTCORNER_SYM |

   768      BOTTOMLEFT_SYM |

   769      BOTTOMCENTER_SYM |

   770      BOTTOMRIGHT_SYM |

   771      BOTTOMRIGHTCORNER_SYM |

   772      LEFTTOP_SYM |

   773      LEFTMIDDLE_SYM |

   774      LEFTBOTTOM_SYM |

   775      RIGHTTOP_SYM |

   776      RIGHTMIDDLE_SYM |

   777      RIGHTBOTTOM_SYM

   778      ;

   779 </pre>

   781 <div class="example">

   782 <p>The following are examples of page selectors (declaration block intentionally

   783 left blank)</p>

   784 <pre>

   785 @page { ... }

   786 @page :left { ... }

   787 @page :right { ... }

   788 @page LandscapeTable { ... }

   789 @page CompanyLetterHead:first { ... } /*  identifier and pseudo page. */

   790 @page:first { ... }

   791 @page toc, index { ... }

   792 @page :blank:first { ... }

   793 </pre>

   795 <p>The following are examples of page-margin boxes

   796 where the declaration blocks are intentionally left blank.</p>

   797 <pre>

   798 @page {

   799  @top-left { ... /* document name */ }

   800  @bottom-center { ... /* page number */}

   801 }

   802 @page :left { @left-middle { ... /* page number in left margin */ }}

   803 @page :right{ @right-middle { ... /* page number in right margins of right pages */}}

   805 @page :left { @bottom-left-corner { ... /* left page numbers */ }}

   806 @page :right { @bottom-right-corner { ... /* right page numbers */ }}

   807 @page :first { @bottom-left-corner { ... /* empty footer on 1st page */ }

   808              @bottom-right-corner { ... /* empty footer */ } }

   809 </pre>

   810 </div>

   812 <h3 id="cascading-and-page-context">Cascading in the page context</h3>

   814 <p>Declarations in page and margin contexts <a href="http://www.w3.org/TR/CSS21/cascade.html">cascade</a> just like declarations in <a href="http://www.w3.org/TR/CSS21/syndata.html#rule-sets">rule sets</a>.</p>

   816 <p>The <dfn>specificity</dfn> of page a selector is computed in a manner

   817 analogous to the computations defined in

   818 the <a href="http://www.w3.org/TR/CSS21/selector.html">Selectors</a> module:

   820 <ul>

   821   <li>Count the number of page type names (= <var>f</var>)

   822     <p class="note">This is 0 or 1.

   823   <li>Count the number of ':first' or ':blank' pseudo-classes (= <var>g</var>)

   824   <li>Count the number of ':left' or ':right' pseudo-classes (= <var>h</var>)

   825 </ul>

   827 <p>

   828   Specificities are compared by comparing the three components in order:

   829   the specificity with <var>f</var> larger a value is more specific;

   830   if the two <var>f</var> values are tied,

   831   then the specificity with a larger <var>g</var> value is more specific;

   832   if the two <var>g</var> values are also tied,

   833   then the specificity with a larger <var>h</var> value is more specific;

   834   if all the values are tied, the two specifities are equal.

   836 <p>

   837   Due to storage limitations,

   838   implementations may have limitations on

   839   the size of <var>f</var>, <var>g</var>, or <var>h</var>.

   840   If so, values higher than the limit must be clamped to that limit,

   841   and not overflow.

   843 <p class="note">

   844   Note: Each comma-separated selectors in the same ''@page'' rule

   845   has its own specificity.

   847 <p class="note">

   848   Note: Repeated occurrances of the same pseudo-classes are allowed

   849   and do increase specificity.

   851 <div class="example">

   853 <p>Some page specificity calculation examples follow:</p>

   854 <pre>

   855 @page { } /* specificity = (0,0,0) */

   856 @page :left { } /* specificity = (0,0,1) */

   857 @page :first { } /* specificity = (0,1,0) */

   858 @page artsy { } /* specificity = (1,0,0) */

   859 @page artsy:left { } /* specificity = (1,0,1) */

   860 @page artsy:first { } /* specificity = (1,1,0) */

   861 </pre>

   862 </div>

   864 <div class="example">

   866 <p>Consider the following usage example:</p>

   867 <pre>

   868 @page {

   869   margin-left: 3cm;

   870 }

   872 @page :left {

   873   margin-left: 4cm;

   874 }

   875 </pre>

   877 <p>Due to the higher specificity of the pseudo-class selector,

   878 the left margin on left pages will be 4cm and all other pages

   879 (the right-facing pages) will have a left margin of 3cm.

   880 </div>

   882 <div class="example">

   883 <p>In this example, the higher specificity of the green rules wins over the red

   884 rule.

   885 Therefore the first page will have blue text in the top-left page-margin box

   886 and green text in the top-right page-margin box,

   887 while subsequent pages will have red text in the page-margin boxes.</p>

   888 <pre>

   889 @page :first {

   890   color: green;

   892   @top-left {

   893     content: "foo";

   894     color: blue;

   895   }

   896   @top-right {

   897     content: "bar";

   898   }

   899 }

   901 @page { color: red;

   902   @top-center {

   903     content: "Page " counter(page);

   904   }

   905 }

   906 </pre>

   907 </div>

   909 <div class="example">

   911 <p>Page contexts cascade, so the following stylesheet would style pages with 25

   912 millimeter margins and 14 point type in the page-margin boxes:</p>

   913 <pre>

   914 @page { margin: 25mm;}

   915 @page { font-size: 14pt;}

   916 </pre>

   917 </div>

   919 <h2 id="margin-boxes">Page-Margin Boxes</h2>

   921   <p>Page-margin boxes are boxes within the page margin that,

   922   like pseudo-elements, can contain generated content.

   924   <p>Page-margin boxes can be used to create page headers and footers,

   925   which are portions of the page set aside for supplementary information

   926   such as the page number or document title.

   928   <div class="example">

   929     <p>Typically, a <dfn>page header</dfn> is located at the top of the page

   930     in documents with a predominately horizontal writing direction

   931     and on the side opposite the <a href="#binding-edge">binding edge</a>

   932     for documents with a predominately vertical writing direction.

   933     One possible design of page headers for horizontally written documents uses the

   934     ''@top-left-corner'', ''@top-left'', ''@top-center'', ''@top-right'' and ''@top-right-corner''

   935     page-margin boxes.

   936     Another design, for vertically written documents, could use the

   937     ''@right-top'', ''@right-middle'', and ''@right-bottom'' page-margin boxes

   938     for <a href="#right-page">right facing pages</a> and

   939     ''@left-top'', ''@left-middle'', and ''@left-bottom''

   940     for <a href="#left-page">left facing pages</a>.

   942     <p>The <dfn>page footer</dfn> is typically at

   943     the opposite end of the page from the page header.

   944     For example, the design of a horizontally written document with a page header

   945     at the top of the page could use the

   946     ''@bottom-left-corner'', ''@bottom-left'', ''@bottom-center'', ''@bottom-right'' and ''@bottom-right-corner''

   947     page-margin boxes as the page footer.

   948     The design of a vertically written document could use

   949     the page-margin boxes of the binding edge of the page for the page footer.

   950   </div>

   952   <p>Page-margin boxes are positioned with respect to the page area

   953   and are independent of page orientation,

   954   for example the top page-margin boxes are above the page area

   955   in both portrait and landscape orientation.

   956   The various page-margin boxes are defined

   957   and illustrated in the diagram below:

   959   <table id="margin-box-def" class="data" summary="defintion of each of the page-margin boxes">

   960     <caption>Table 1 Page-Margin Box Definitions</caption>

   961     <thead>

   962       <tr>

   963         <th>Box</th>

   964         <th>Description</th>

   965         <th>Placement</th>

   966       </tr>

   967     </thead>

   968     <tbody>

   969       <tr id="top-margin-boxes-def">

   970         <th id="top-left-corner-box-def">top-left-corner</th>

   971         <td>a fixed-size box defined by the intersection of the top and left margins of the

   972         page box</td>

   973         <td><img src="TopLeftCornerBox.png" alt="the top left corner box with margin, border, and padding, nested within intersection of the page's top and left margins"

   974         height="47" width="181"></td>

   975       </tr>

   976       <tr id="top-left-box-def">

   977         <th>top-left</th>

   978         <td>a variable-width box filling the top page margin between the top-left-corner

   979         and top-center page-margin boxes</td>

   980         <td><img src="TopLeftMarginBox.png" alt="the top left box with margin, border, and padding, nested in the page's top margin next to the top left corner box"

   981         height="47" width="181"></td>

   982       </tr>

   983       <tr id="top-center-box-def">

   984         <th>top-center</th>

   985         <td>a variable-width box centered horizontally between the page's left and right

   986         border edges and filling the page top margin between the top-left and top-right

   987         page-margin boxes</td>

   988         <td><img src="TopCenterMarginBox.png" alt="the top center box with margin, border, and padding, centered within the page's top margin"

   989         height="47" width="181"></td>

   990       </tr>

   991       <tr id="top-right-box-def">

   992         <th>top-right</th>

   993         <td>a variable-width box filling the top page margin between the top-center and

   994         top-right-corner page-margin boxes</td>

   995         <td><img src="TopRightMarginBox.png" alt="the top right box with margin, border, and padding, nested within the page's top margin"

   996         height="47" width="181"></td>

   997       </tr>

   998       <tr>

   999         <th id="top-right-corner-box-def">top-right-corner</th>

  1000         <td>a fixed-size box defined by the intersection of the top and right margins of

  1001         the page box</td>

  1002         <td><img src="TopRightCornerMarginBox.png" alt="the top right corner box with margin, border, and padding, nested within the intersection of the page's top and right margin"

  1003         height="47" width="181"></td>

  1004       </tr>

  1005       <tr id="left-margin-boxes-def">

  1006         <th id="left-top-box-def">left-top</th>

  1007         <td>a variable-height box filling the left page margin between the top-left-corner

  1008         and left-middle page-margin boxes</td>

  1009         <td rowspan="3"><img src="LeftMarginBoxes.png" alt="left-top, left-middle, and left-bottom page-margin boxes in the page box's left margin"

  1010         height="226" width="181"></td>

  1011       </tr>

  1012       <tr id="left-middle-box-def">

  1013         <th>left-middle</th>

  1014         <td>a variable-height box centered vertically between the page's top and bottom

  1015         border edges and filling the left page margin between the left-top and

  1016         left-bottom page-margin boxes</td>

  1017       </tr>

  1018       <tr id="left-bottom-box-def">

  1019         <th>left-bottom</th>

  1020         <td>a variable-height box filling the left page margin between the left-middle and

  1021         bottom-left-corner page-margin boxes</td>

  1022       </tr>

  1023       <tr id="right-margin-boxes-def">

  1024         <th id="right-top-box-def">right-top</th>

  1025         <td>a variable-height box filling the right page margin between the

  1026         top-right-corner and right-middle page-margin boxes</td>

  1027         <td rowspan="3"><img src="RightMarginBoxes.png" alt="right-top, right-middle, and right-bottom page-margin boxes in the page box's right margin"

  1028         height="226" width="181"></td>

  1029       </tr>

  1030       <tr id="right-middle-box-def">

  1031         <th>right-middle</th>

  1032         <td>a variable-height box centered vertically between the page's top and bottom

  1033         border edges and filling the right page margin between the right-top and

  1034         right-bottom page-margin boxes</td>

  1035       </tr>

  1036       <tr id="right-bottom-box-def">

  1037         <th>right-bottom</th>

  1038         <td>a variable-height box filling the right page margin between the right-middle

  1039         and bottom-right-corner page-margin boxes</td>

  1040       </tr>

  1041       <tr id="bottom-margin-boxes-def">

  1042         <th id="bottom-left-corner-box-def">bottom-left-corner</th>

  1043         <td>a fixed-size box defined by the intersection of the bottom and left margins of

  1044         the page box</td>

  1045         <td><img src="BottomLeftCornerBox.png" alt="bottom left corner box with margin, border, and padding, nested within the page margin at the intersection of the left and bottom page margins"

  1046         height="48" width="181"></td>

  1047       </tr>

  1048       <tr id="bottom-left-box-def">

  1049         <th>bottom-left</th>

  1050         <td>a variable-width box filling the bottom page margin between the

  1051         bottom-left-corner and bottom-center page-margin boxes</td>

  1052         <td><img src="BottomLeftMarginBox.png" alt="bottom left page-margin box with margin, border, and padding, nested within the page's bottom margin next to the bottom-left-corner box"

  1053         height="48" width="181"></td>

  1054       </tr>

  1055       <tr id="bottom-center-box-def">

  1056         <th>bottom-center</th>

  1057         <td>a variable-width box centered horizontally between the page's left and right

  1058         border edges and filling the bottom page margin between the bottom-left and

  1059         bottom-right page-margin boxes</td>

  1060         <td style="vertical-align: middle;"><img src="BottomCenterMarginBox.png" alt="bottom center box with margin, border, and padding, nested within the page's bottom margin and centered on the page"

  1061         height="48" width="181"></td>

  1062       </tr>

  1063       <tr id="bottom-right-box-def">

  1064         <th>bottom-right</th>

  1065         <td>a variable-width box filling the bottom page margin between the bottom-center

  1066         and bottom-right-corner page-margin boxes</td>

  1067         <td><img src="BottomRightMarginBox.png" alt="bottom right page-margin box with margin, border, and padding, nested within the page's bottom margin and next to the bottom-right-corner box"

  1068         height="48" width="181"></td>

  1069       </tr>

  1070       <tr id="bottom-right-corner-box-def">

  1071         <th>bottom-right-corner</th>

  1072         <td>a fixed-size box defined by the intersection of the bottom and right margins of

  1073         the page box</td>

  1074         <td><img src="BottomRightCornerBox.png" alt="bottom right corner box with margin, border, and padding, nested within the page margin at the intersection of the right and bottom page margins"

  1075         height="48" width="181"></td>

  1076       </tr>

  1077     </tbody>

  1078   </table>

  1080 <h3 id="margin-at-rules">At-rules for page-margin boxes</h3>

  1082 <p>Page-margin boxes are created by

  1083 <a href="#margin-at-rules">margin at-rules</a>

  1084 inside the <a href="#page-context">page context</a>.

  1085 These rules should come after any declarations in the page context as legacy

  1086 clients may not handle declarations after margin at-rules correctly.</p>

  1088 <p>A <dfn id="margin-at-rule">margin at-rule</dfn> consists of an

  1089 <a href="#specializatons-of-ATKEYWORD">ATKEYWORD</a>

  1090 that identifies the page-margin box

  1091 (e.g. <span class="css">'@top-left'</span>) and a block of declarations (said

  1092 to be in the <dfn id="margin-context">margin context</dfn>).</p>

  1094 <div class="example">

  1096 <p>The following style sheet establishes a page header containing the title

  1097 ("Hamlet") on the left side and the page number, preceded by "Page ", on the

  1098 right side:</p>

  1099 <pre>

  1100 @page {

  1101   size: 8.5in 11in;

  1102   margin: 10%;

  1104   @top-left {

  1105     content: "Hamlet";

  1106   }

  1107   @top-right {

  1108     content: "Page " counter(page);

  1109   }

  1110 }

  1111 </pre>

  1112 </div>

  1115 <h3 id="populating-margin-boxes">Populating page-margin boxes</h3>

  1117 <p>As with the '':before'' and '':after'' pseudo-elements,

  1118 a specified 'content' of ''normal'' on a page-margin box computes to ''none'',

  1119 and the page-margin box is <dfn>generated</dfn>

  1120 if and only if the computed value

  1121 of its 'content' property is not 'none'.

  1122 Otherwise it behaves as if it had ''display: none''.

  1124 <div class="example">

  1125 <p>The following style sheet creates a green box in each corner of the page

  1126 except the bottom-left corner.</p>

  1127 <pre>

  1128   @page {

  1129     @top-left-corner { content: " "; border: solid green; }

  1130     @top-right-corner { content: url(foo.png); border: solid green; }

  1131     @bottom-right-corner { content: counter(page); border: solid green; }

  1132     @bottom-left-corner { content: normal; border: solid green; }

  1133   }

  1134 </pre>

  1135 </div>

  1137 <h3 id="margin-dimension">Computing Page-margin Box Dimensions</h3>

  1139 <p>The width and height of each page-margin box is determined by the rules

  1140 below. These rules define the equivalent of CSS2.1 Sections 10.3 and

  1141 10.6 for page-margin boxes.</p>

  1143 <p>The rules for applying 'min-height', 'max-height', 'min-width', and

  1144 'max-width' [[!CSS21]] do apply to page-margin boxes and may imply

  1145 a recalculation of the width, height, and/or margins

  1146 if the dimensions resulting from the specified 'width' or 'height'

  1147 violate their constraints.

  1148 If the UA does not support the 'min-height' or 'min-width' properties

  1149 then it must behave as if 'min-height' and 'min-width' were always zero.

  1151 <h4 id="margin-box-terms"><a id="max-margin-dimension"></a>Page-Margin Box Layout Terminology</h4>

  1153   <p>In addition to the box model definitions in CSS2.1 [[!CSS21]],

  1154   and the sizing terms in CSS Intrinsic Sizing [[!CSS3-SIZING]],

  1155   the following terms are defined for use

  1156   in the subsequent page-margin box calculations:

  1158   <dl>

  1160     <dt><dfn>available width</dfn></dt>

  1161     <dd>The sum of the page’s

  1162       left border width, left padding, <a href="#page-box">page area</a> width,

  1163       right padding, and right border width.

  1164       In other words, it is the distance between

  1165       the <a href="#page-box">page box</a>’s left right border edges.

  1166       This quantity is used  when calculating dimensions

  1167       of the top and bottom page-margin boxes.

  1169     <dt><dfn>available height</dfn></dt>

  1170     <dd>The sum of the page’s

  1171       top border width, top padding, <a href="#page-box">page area</a> height,

  1172       bottom padding, and bottom border width.

  1173       In other words, it is the distance between

  1174       the <a href="#page-box">page box</a>’s top bottom border edges.

  1175       This quantity is used when calculating dimensions

  1176       of the left and right page-margin boxes.

  1178     <dt><dfn>outer width</dfn></dt>

  1179     <dd>The width of the

  1180       <a href="http://www.w3.org/TR/CSS21/box.html#outer-edge">outer edge</a>,

  1181       as defined in [[!CSS21]].

  1183     <dt><dfn>outer min width</dfn></dt>

  1184     <dd>Like the <i>outer width</i>, except that

  1185     <a href="http://www.w3.org/TR/css3-sizing/#min-content">''min-content''</a>

  1186     is used when the width is ''auto''.

  1188     <dt><dfn>outer max width</dfn></dt>

  1189     <dd>Like the <i>outer width</i>, except that

  1190     <a href="http://www.w3.org/TR/css3-sizing/#max-content">''max-content''</a>

  1191     is used when 'width' is ''auto''.

  1192   </dl>

  1194   <p>The <dfn>containing block</dfn> for a corner page-margin box is

  1195   the rectangle defined by the intersection of the two page margins meeting at that corner.

  1197   <p>For all other page-margin boxes,

  1198   the <dfn>containing block</dfn> is the rectangle

  1199   formed by the encapsulating page margin minus the containing blocks of the

  1200   adjacent corners' page-margin boxes.

  1201   This means that the size of this containing block is given

  1202   in one dimension by the used page margin and in the other dimension

  1203   by the <i>available width</i>

  1204   (for top and bottom page-margin boxes) or

  1205   <i>available height</i>

  1206   (for left and right page-margin boxes).</p>

  1208 <h4 id="variable-sizing">

  1209 Page-Margin Box Variable Dimension Computation Rules</h4>

  1211 <p>The following rules apply to 'top-left', 'top-center' and 'top-right'

  1212 page-margin boxes,

  1213 which are referred to as A, B, and C, respectively, in this section.</p>

  1215 <h5 id="variable-auto-margins">Margins</h5>

  1217 <p>If the 'margin-left' or 'margin-right' property of any of the three boxes

  1218 computes to ''auto'', the used value is zero.</p>

  1220 <h5 id="variable-auto-sizing">Resolving ''auto'' widths</h5>

  1222 <p>The following algorithm determines the used width of each box.

  1223 For this purpose, boxes that are not <i>generated</i>

  1224 are assumed to have a 'width' and an <i>outer width</i> of zero.

  1225 </p>

  1227 <p class="note">

  1228 Note: The high-level goals are (in order of priority) to center the middle

  1229 box (B) if it is generated, to minimize overflow and overlap, and to

  1230 distribute space proportionally to the amount of content.</p>

  1232   <p>If the middle box (B) is not <i>generated</i>,

  1233   distribute the <i>available width</i> to A and C as follows:

  1235   <ul>

  1236     <li>

  1237       If only one box has 'width: auto',

  1238       its used width is resolved so that

  1239       the sum of the <i>outer width</i>s equals <i>available width</i>.

  1240     </li>

  1242     <li id="flex-fit">

  1243       If A and C both have 'width: auto', distribute the space to each box as follows:

  1244       <ol>

  1245         <li>If the sum of the outer <i>max-content widths</i> is less than the <i>available width</i>,

  1246             call that difference the <i>flex space</i>.

  1247             Calculate each box's <i>flex factor</i> as proportional to

  1248             its outer <i>max-content width</i>,

  1249             and set its used outer width to:

  1250               <pre><i>max-content width</i> + <i>flex space</i> × <i>flex factor</i> ÷ ∑<i>flex factors</i></pre>

  1251         <li>Otherwise if the sum of the outer <i>min-content widths</i> is less than the <i>available width</i>,

  1252             call that difference the <i>flex space</i>

  1253             calculate each box's <i>flex factor</i> as proportional to

  1254             its <i>max-content</i> minus <i>min-content</i>,

  1255             and set its used outer width to:

  1256               <pre><i>min-content width</i> + <i>flex space</i> × <i>flex factor</i> ÷ ∑<i>flex factors</i></pre>

  1257         <li>Otherwise,

  1258             calculate its outer size as in the previous case,

  1259             but set each box's <i>flex factor</i> as proportional to

  1260             its outer <i>min-content width</i>.

  1261       </ol>

  1262       In each case, both <i>flex factors</i> are assumed to be ''1'' if their sum is equal to zero.

  1263     </li>

  1264   </ul>

  1266   <p>If the middle box (B) is <i>generated</i>,

  1267   determine the ''auto'' widths of A, B, and C as follows:

  1269   <ol>

  1270     <li>

  1271       First, resolve any ''auto'' width of the middle box (B):

  1272       Assume there are two boxes, B and AC,

  1273       where each of AC's dimensions is double the maximum of A and C.

  1274       (This preserves B's centering.)

  1275       Distribute the space to these two boxes (B and the imaginary AC)

  1276       as described for A and C <a href="#fit2">above</a>.

  1277     <li>

  1278       Then, resolve any ''auto'' widths of the side boxes (A and C)

  1279       by setting that box's outer width to

  1280       <pre>(<i>available width</i> &minus; <i>used outer size of B</i>) ÷ 2<pre>

  1281     </li>

  1282   </ol>

  1284 <h5 id="variable-minmax">Handling 'min-width' and 'max-width'</h5>

  1286 <p>

  1287   The 'min-width' and 'max-width' properties [[CSS21]] apply to page-margin

  1288   boxes in the variable dimension like on normal elements, except that the

  1289   three boxes on the same side are considered together.

  1290 </p>

  1292 <p>

  1293   More precisely:

  1294 </p>

  1296 <ol>

  1297   <li>

  1298     The tentative used widths are calculated

  1299     (without 'min-width' and 'max-width') following the rules under

  1300     <a href="#marginbox-variabledim-with">Resolving ''auto'' widths</a>

  1301     above.

  1302   </li>

  1303   <li>

  1304     If the tentative used width of any of the three boxes

  1305     is greater than 'max-width', the rules above are applied again,

  1306     but this time using the computed value of 'max-width'

  1307     as the computed value for 'width'.

  1308   </li>

  1309   <li>

  1310     If the resulting width of any of the three boxes

  1311     is smaller than 'min-width', the rules above are applied again,

  1312     but this time using the value of 'min-width'

  1313     as the computed value for 'width'.

  1314   </li>

  1315 </ol>

  1317 <h5 id="variable-position">Positioning</h5>

  1319 <p>

  1320   Once the dimensions of the boxes are determined,

  1321   they are positioned as follows:

  1322 </p>

  1324 <ul>

  1325   <li>The left outer edge of A is flush with the left edge of the

  1326       containing block</li>

  1327   <li>The outer area of B is centered in the containing block.</li>

  1328   <li>The right outer edge of C is flush with the right edge of the

  1329       containing block.</li>

  1330 </ul>

  1332 <h5 id="variable-mapping">Boxes on other sides</h5>

  1334 <p>The used values for 'bottom-left', 'bottom-center' and 'bottom-right'

  1335 page-margin boxes are established by the same rules as

  1336 for 'top-left', 'top-center', and 'top-right', respectively.</p>

  1338 <p>The used values for 'left-top', 'left-middle' and 'left-bottom' boxes are

  1339 established by the same rules, with "width" replaced by "height", "left" by

  1340 "top", "right" by "bottom" and "center" by "middle".</p>

  1342 <p>The used values for 'right-top', 'right-middle' and 'right-bottom'

  1343 page-margin boxes

  1344 are established by the same rules as for 'left-top', 'left-middle' and

  1345 'left-bottom', respectively.</p>

  1347 <h4 id="fixed-sizing">Page-Margin Box Fixed Dimension Computation Rules</h4>

  1349 <p>The rules below are used to calculate the used values of each

  1350 'top-left-corner', 'top-left', 'top-center', 'top-right', and

  1351 'top-right-corner' page-margin box's 'height', 'margin-top', and 'margin-bottom'

  1352 properties:</p>

  1354 <ol>

  1355   <li>The following constraint must hold among the used values of the margin

  1356   box's properties:

  1357   <p>'margin-top' + 'border-top-width' + 'padding-top' + 'height' +

  1358   'padding-bottom' + 'border-bottom-width' + 'margin-bottom' = top page margin

  1360   <li>If 'border-top-width' + 'padding-top' + 'height' (if it is not ''auto'')

  1361   + 'padding-bottom' + 'border-bottom-width', plus 'margin-top' and/or

  1362   'margin-bottom' if not ''auto'', is larger than the height of the top page

  1363   margin, then any ''auto'' values for 'margin-top' or 'margin-bottom' are, for

  1364   the following rules, treated as zero.

  1366   <li>If at this point all of 'height', 'margin-top', and 'margin-bottom'

  1367   have a computed value other than ''auto'', the values are said to be

  1368   "over-constrained". In this case, the specified value of 'margin-top' is

  1369   treated as 'auto'.

  1371   <li>If there is now exactly one value specified as 'auto', its used value

  1372   follows from the equality.

  1374   <li>If 'height' is set to 'auto', any other 'auto' values become '0' and

  1375   'height' follows from the resulting equality

  1377   <li>If both 'margin-top' and 'margin-bottom' are 'auto',

  1378   their used values are equal.

  1379   This vertically centers the page-margin box content

  1380   within the top page margin.

  1381 </ol>

  1383 <p>The same rules apply to the bottom page-margin boxes (bottom-left-corner,

  1384 bottom-left, bottom-center, bottom-right, and bottom-right-corner), except that

  1385 in the overconstrained case, the 'margin-bottom' is ignored rather than the

  1386 'margin-top'.</p>

  1388 <p>Analogous rules govern the properties for the left and right

  1389 page-margin boxes with respect to 'width'

  1390 (top-left-corner, left-top, left-middle, left-bottom, and

  1391 bottom-left-corner; top-right-corner, right-top, right-middle, right-bottom,

  1392 bottom-right-corner), with 'top' replaced by 'left', 'bottom' replaced by

  1393 'right', and 'height' replaced by 'width'.

  1394 In the overconstrained case for left (right) page-margin boxes,

  1395 the specified value of 'margin-left' ('margin-right') is ignored.</p>

  1397 <h3 id="margin-box-ex">Page-margin box examples</h3>

  1399 <p>The following is a collection of examples of page-margin box usage.</p>

  1401 <div class="example">

  1403 <p>Here is an example of a page with only a top-left header:</p>

  1404 <pre>

  1405 @page {

  1406 @top-left { content: "Header in Left Cell (top-left)" }

  1407 }

  1408 </pre>

  1410 <p>Because there are no contents defined for the top-center or the top-right

  1411 page-margin boxes, the extent of the top-left page-margin box

  1412 is allowed to cross the center of the page box.</p>

  1414 <p><img alt="Header Example 1" src="header-ex-1.png" height="177" width="737"></p>

  1415 </div>

  1417 <div class="example">

  1419 <p>The following is an example of a page with a centered header:</p>

  1420 <pre>

  1421 @page {

  1422 @top-center { content: "Header in Center Cell (top-center)" }

  1423 }

  1424 </pre>

  1426 <p><img alt="Header Example 2" src="header-ex-2.png" height="177" width="737"></p>

  1427 </div>

  1429 <div class="example">

  1431 <p>The following is an example of a page with a single header in the top-right

  1432 page-margin box:</p>

  1433 <pre>

  1434 @page {

  1435 @top-right { content: "Header in Right Cell (top-right)" }

  1436 }

  1437 </pre>

  1439 <p>Because the content of the center cell is empty, the extent of the top-right

  1440 page-margin box is allowed to cross the center of the page box.</p>

  1442 <p><img alt="Header Example 3" src="header-ex-3.png" height="177" width="737"></p>

  1443 </div>

  1445 <div class="example">

  1447 <p>The following is an example of a page with a top-center and a top-left header:</p>

  1448 <pre>

  1449 @page {

  1450 @top-left { content: "Left Cell (top-left)" }

  1451 @top-center { content: "Header in Center Cell (top-center)" }

  1452 }

  1453 </pre>

  1455 <p><img alt="Header Example 4" src="header-ex-4.png" height="177" width="737"></p>

  1456 </div>

  1458 <div class="example">

  1460 <p>The following is an example of a page with a top-center and a top-right header:</p>

  1461 <pre>

  1462 @page {

  1463 @top-center { content: "Header in Center Cell (top-center)" }

  1464 @top-right { content: "Right Cell (top-right)" }

  1465 }

  1466 </pre>

  1468 <p><img alt="Header Example 5" src="header-ex-5.png" height="177" width="737"></p>

  1469 </div>

  1471 <div class="example">

  1473 <p>The following is an example of a page with top-left and top-right headers:</p>

  1474 <pre>

  1475 @page {

  1476 @top-left { content: "Header in top-left with approx. "

  1477                    "twice as many words as right cell." }

  1478 @top-right { content: "Right cell (top-right)" }

  1479 }

  1480 </pre>

  1482 <p>Because there are no center cell contents, the extent of the top-left is

  1483 allowed to cross the center of the page box.</p>

  1485 <p><img alt="Header Example 6" src="header-ex-6.png" height="177" width="737"></p>

  1486 </div>

  1488 <h2 id="page-properties">Page Properties</h2>

  1489 <div>

  1491 <p>The following properties, when used in the <a href="#page-context">page

  1492 context</a>, apply to the page box:</p>

  1494 <ul>

  1495   <li><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a></li>

  1496   <li><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a></li>

  1497   <li><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a></li>

  1498   <li><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a></li>

  1499   <li><a href="http://www.w3.org/TR/CSS21/visuren.html#direction">direction</a>

  1500   <li><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a></li>

  1501   <li><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a></li>

  1502   <li><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a></li>

  1503   <li><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  1504   <li><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a></li>

  1505   <li><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  1506   <li><a href="#page-size">size</a></li>

  1507   <li><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a></li>

  1508   <li><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a></li>

  1509 </ul>

  1511 <p>The following properties, when used in a <a href="#margin-at-rule">margin

  1512 context</a>, apply to page-margin boxes and their content:</p>

  1514 <ul>

  1515   <li><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a>

  1516   <li><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a>

  1517   <li><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a>

  1518   <li><a href="http://www.w3.org/TR/CSS21/generate.html#content">content</a>

  1519   <li><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a></li>

  1520   <li><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a>

  1521   <li><a href="http://www.w3.org/TR/CSS21/visudet.html#the-height-property">height</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-heights">properties</a>

  1522   <li><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a>

  1523   <li><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a>

  1524   <li><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  1525   <li><a href="http://www.w3.org/TR/CSS21/visufx.html#overflow">overflow</a>

  1526   <li><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a>

  1527   <li><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  1528   <li><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a>

  1529   <li><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">vertical-align</a>

  1530   <li><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a>

  1531   <li><a href="http://www.w3.org/TR/CSS21/visudet.html#the-width-property">width</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-widths">properties</a>

  1532   <li><a href="http://www.w3.org/TR/CSS21/visuren.html#z-index">z-index</a>

  1533 </ul>

  1535 <p>A detailed list of properties that <em class="RFC2119">MUST</em> be supported

  1536 within page and margin contexts by a conforming implementation can be found in

  1537 <a href="#properties-list">Appendix A</a>.</p>

  1539 <p>Other properties defined by [[!CSS21]] do not apply in these contexts. Behavior

  1540 for properties not included in CSS 2.1 and not listed here or in Appendix A is

  1541 undefined.</p>

  1543 <p class="note">

  1544 Note: The intent of leaving other properties undefined is to allow the gradual

  1545 addition of appropriate CSS3 properties as they emerge, without having to

  1546 update this specification with each addition.</p>

  1548 <p><a href="http://www.w3.org/TR/CSS21/cascade.html#value-stages">As with

  1549 elements in the document</a>, both the page context and the margin context

  1550 have a computed value for every property, even if that property does not

  1551 apply to the page or page-margin box.</p>

  1553 <p>The normal rules for CSS properties apply with the following exceptions:</p>

  1555 <ul>

  1556   <li>page-margin boxes inherit from the page context.

  1557   The page context inherits from the root element.

  1558   However, since the previous revision of CSS Paged

  1559   Media Level 3 did not specify this point, an implementation that sets

  1560   inherited properties in the page context to their initial values (as for the

  1561   root element) is also conformant to CSS Paged Media Level 3. Note that this

  1562   exception will be removed in Level 4.

  1563   <li>Values in units of ''em'' and ''ex'' are interpreted relative to the font

  1564   associated with their context. When used on the 'font-size' property in the

  1565   margin context, they are relative to the font of the page context. When used

  1566   on the 'font-size' property in the page context, they are relative to the

  1567   'font-size' of the root element. However, since a previous revision of CSS

  1568   Paged Media Level 3 was ambiguous on this point, an implementation that

  1569   treats ''em'' and ''ex'' on 'font-size' as relative to the initial value is

  1570   also conformant to CSS Paged Media Level 3. Note that this exception will

  1571   be removed in Level 4.

  1572   <li>Percentage values on the margin and padding properties are relative to the

  1573   dimensions of the containing block. For right and left values, percentages are

  1574   relative to the width of the containing block; for top and bottom values,

  1575   percentages are relative to the height of the containing block.</li>

  1576   <li>The used values of 'width' and 'height' have special computation rules

  1577   for page boxes and page-margin boxes; see <a href="#page-size">Page Size</a>

  1578   and <a href="#margin-box-dimensions">Computing Page-Margin Box Dimensions</a>.

  1579   <li>The page background is positioned and painted

  1580     <a href="#painting">as described above</a>.

  1581   <li>The rules for counter scoping are modified <a href="page-based-counters">as

  1582   described below</a>.</li>

  1583   <li>

  1584     As on the '::before' and '::after' pseudo-elements,

  1585     the ''normal'' value of the 'content' property computes to ''none''

  1586     on page-margin boxes.

  1587   </li>

  1588   <li>On page-margin boxes, the 'vertical-align' property behaves

  1589   <a href="http://www.w3.org/TR/CSS21/tables.html#height-layout">as specified for table cells</a>.

  1590   It <em>always</em> performs alignment in the vertical dimension,

  1591   regardless of writing mode.

  1592 </ul>

  1594 <p>It is <em class="RFC2119">recommended</em> that user agents establish a default

  1595 page margin via the user agent stylesheet that includes any non-printable area.

  1596 It is further <em class="RFC2119">recommended</em> that authors assume that the

  1597 default page area will not include unprintable regions.</p>

  1599 <h3 id="page-based-counters">Page-based counters</h3>

  1601 <p>Counters can be defined and controlled within an <span class="css">'@page'</span>

  1602 rule, and used as content in page-margin boxes.

  1603 This is useful for maintaining a page count.</p>

  1605 <p>A 'counter-increment' within either a page or margin context causes the counter

  1606 to increment with the generation of each page box.</p>

  1608 <p>If a counter is reset or incremented within the page context, it is in scope

  1609 for all page-margin boxes and obscures all counters of the same name within the

  1610 document.</p>

  1612 <p>If a counter is reset or incremented within a margin context, it is in scope

  1613 for that page-margin box and obscures any counters of the same name

  1614 in both the page context and the document.</p>

  1616 <p>If a counter that has not been reset or incremented within the margin context

  1617 or the page context is used by counter() or counters() in the margin context,

  1618 then the resultant value is exactly

  1619 as if the page-margin box were an element within

  1620 the document at the start of the page, inside the deepest element in the normal

  1621 flow that spans the page break. Use of the counter in this way does not affect

  1622 the calculation of the counter's value.</p>

  1624 <p>

  1625   A counter named ''page'' is automatically created

  1626   and incremented by 1 on every page of the document,

  1627   unless the 'counter-increment' property in the <i>page context</i>

  1628   explicitly specifies a different increment for the ''page'' counter.

  1629   The implied ''page'' counter is a real counter,

  1630   and can be directly affected using the 'counter-increment' and 'counter-reset' properties

  1631   when named explicitly in those properties.

  1632   It can also be used in the 'counter()' and 'counters()' function forms.

  1633 </p>

  1635 <div class="example">

  1636 <p>The following rules result in the placement of the current page number in the

  1637 middle of the outside margin of each page.</p>

  1638 <pre>

  1639 @page {

  1640   margin: 10%;

  1642   @top-center {

  1643     font-family: sans-serif;

  1644     font-weight: bold;

  1645     font-size: 2em;

  1646     content: counter(page);

  1647   }

  1648 }

  1649 </pre>

  1651 <p>Adding the following rule will make all pages even-numbered.</p>

  1652 <pre>

  1653 @page {

  1654   counter-increment: page 2;

  1655 }

  1656 </pre>

  1657 </div>

  1659 <p>Additionally, a counter named ''pages'' is automatically created by the UA.

  1660 Its value is always the total number of pages in the document. (In continuous

  1661 media this is always 1.) The value of ''pages'' cannot be manipulated: while

  1662 'counter-reset' and 'counter-increment' statements that set it are valid, they

  1663 have no effect.

  1665 <p>In all other respects, page-associated counters behave as described in

  1666 [[!CSS21]], <a href="TR/CSS21/generate.html#scope">Nested Counters and

  1667 Scope</a> and <a href="http://www.w3.org/TR/CSS21/syndata.html#counter">Counters</a>.</p>

  1669 <h3 id="margin-text-alignment">Page-margin boxes and default values</h3>

  1671 <p>Properties used within page or margin contexts take their initial values from

  1672 their respective property definitions; however, user agents must behave as

  1673 though the values in the following table were established by rules in the UA

  1674 default style sheet.</p>

  1675 <table id="margin-values" class="data" summary="definition of page-margin box default properties">

  1676   <caption>Table 2. Default values for Page-Margin Boxes</caption>

  1677   <thead>

  1678     <tr>

  1679       <th>Page-margin box</th>

  1680       <th><span class="property">'text-align'</span></th>

  1681       <th><span class="property">'vertical-align'</span></th>

  1682     </tr>

  1683   </thead>

  1684   <tbody>

  1685     <tr>

  1686       <td><a href="#top-left-corner-box-def">top-left-corner</a></td>

  1687       <td>right</td>

  1688       <td>middle</td>

  1689       </tr>

  1690     <tr>

  1691       <td><a href="#top-left-box-def">top-left</a></td>

  1692       <td>left</td>

  1693       <td>middle</td>

  1694       </tr>

  1695     <tr>

  1696       <td><a href="#top-center-box-def">top-center</a></td>

  1697       <td>center</td>

  1698       <td>middle</td>

  1699       </tr>

  1700     <tr>

  1701       <td><a href="#top-right-box-def">top-right</a></td>

  1702       <td>right</td>

  1703       <td>middle</td>

  1704       </tr>

  1705     <tr>

  1706       <td><a href="#top-right-corner-box-def">top-right-corner</a></td>

  1707       <td>left</td>

  1708       <td>middle</td>

  1709       </tr>

  1710     <tr>

  1711       <td><a href="#left-top-box-def">left-top</a></td>

  1712       <td>center</td>

  1713       <td>top</td>

  1714       </tr>

  1715     <tr>

  1716       <td><a href="#left-middle-box-def">left-middle</a></td>

  1717       <td>center</td>

  1718       <td>middle</td>

  1719       </tr>

  1720     <tr>

  1721       <td><a href="#left-bottom-box-def">left-bottom</a></td>

  1722       <td>center</td>

  1723       <td>bottom</td>

  1724       </tr>

  1725     <tr>

  1726       <td><a href="#right-top-box-def">right-top</a></td>

  1727       <td>center</td>

  1728       <td>top</td>

  1729       </tr>

  1730     <tr>

  1731       <td><a href="#right-middle-box-def">right-middle</a></td>

  1732       <td>center</td>

  1733       <td>middle</td>

  1734       </tr>

  1735     <tr>

  1736       <td><a href="#right-bottom-box-def">right-bottom</a></td>

  1737       <td>center</td>

  1738       <td>bottom</td>

  1739       </tr>

  1740     <tr>

  1741       <td><a href="#bottom-left-corner-box-def">bottom-left-corner</a></td>

  1742       <td>right</td>

  1743       <td>middle</td>

  1744       </tr>

  1745     <tr>

  1746       <td><a href="#bottom-left-box-def">bottom-left</a></td>

  1747       <td>left</td>

  1748       <td>middle</td>

  1749       </tr>

  1750     <tr>

  1751       <td><a href="#bottom-center-box-def">bottom-center</a></td>

  1752       <td>center</td>

  1753       <td>middle</td>

  1754       </tr>

  1755     <tr>

  1756       <td><a href="#bottom-right-box-def">bottom-right</a></td>

  1757       <td>right</td>

  1758       <td>middle</td>

  1759       </tr>

  1760     <tr>

  1761       <td><a href="#bottom-right-corner-box-def">bottom-right-corner</a></td>

  1762       <td>left</td>

  1763       <td>middle</td>

  1764     </tr>

  1765   </tbody>

  1766 </table>

  1768 <div class="example">

  1770 <p>This example style sheet could be used to create a centered header with the

  1771 current chapter name:</p>

  1772 <pre>body {counter-reset: chapter;}

  1773 div.chapter {counter-increment: chapter;}

  1774 @page {

  1775 margin: 10%;

  1776 @top-center { content: "Chapter" counter(chapter) }

  1777 }

  1778 </pre>

  1779 </div>

  1781 <h2 id="page-size">Page Size</h2>

  1783 <p>People around the world use many different paper sizes. It is a goal of this

  1784 specification that web content should be adaptable to a range of different

  1785 sizes without having to write a specific style sheet for each paper size.</p>

  1787 <p>However, in some situations it is important that a certain page size achieves a

  1788 certain style. One way to achieve this goal is to utilize the 'size' property,

  1789 which indicates that the document should preferentially be displayed on a

  1790 surface of a certain size; another method is to use Media Queries [[MEDIAQ]]

  1791 which allow different style sheets to be applied to different page sizes.</p>

  1793 <h3 id="page-size-prop">Page size: the 'size' property</h3>

  1795 <table class="propdef" summary="definition of the size property">

  1796   <tr>

  1797     <th>Name:

  1798     <td><dfn id="size">size</dfn>

  1799   <tr>

  1800     <th>Value:

  1801     <td>&lt;length&gt;{1,2} | auto | [ &lt;page-size&gt; || [ portrait | landscape] ]

  1802   <tr>

  1803     <th>Initial:

  1804     <td>auto

  1805   <tr>

  1806     <td><em>Applies to:</em>

  1807     <td>page context

  1808   <tr>

  1809     <th>Inherited:

  1810     <td>N/A

  1811   <tr>

  1812     <th>Percentages:

  1813     <td>N/A

  1814   <tr>

  1815     <th>Media:

  1816     <td>paged

  1817   <tr>

  1818     <td><em>Computed value:</em>

  1819     <td>specified value

  1820 </table>

  1822 <p>This property specifies the target size and orientation of the

  1823 <a href="#page-box">page box</a>’s containing block.

  1824 In the general case, where one page box is rendered onto one <a href="#page-sheet">page sheet</a>,

  1825 the 'size' property also indicates the size of the destination page sheet.

  1827 <p>The size of a page box can either be "absolute" (fixed size) or "scalable"

  1828 (i.e., fitting available sheet sizes).

  1829 The first three values in the table below can be used to create scalable page

  1830 boxes.

  1831 Other values define a fixed-size page box, and thereby indicate the preferred

  1832 output media size. When possible, output should be rendered on the media size

  1833 indicated.

  1834 If the specified size is not available, the rules for

  1835 <a href="#renderingpages">transposing a page box to a different size</a>

  1836 apply.</p>

  1838 <p>If a <code>size</code> property declaration is qualified by a ''width'',

  1839 ''height'', ''device-width'', ''device-height'', ''aspect-ratio'',

  1840 ''device-aspect-ratio'' or ''orientation''

  1841 media query [[!MEDIAQ]] (or other conditional on the size of the paper), then

  1842 the declaration must be

  1843 <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignored</a>. Media

  1844 queries do not honor 'size': they assume the paper size that would be chosen

  1845 if no @page rules were specified.</p>

  1847 <p class=issue>It would be useful if media queries could respond at least

  1848 to sizes specified on an unqualified @page.

  1850 <div class="example">

  1851   <p>In the following example

  1852   <pre>

  1853   @page {

  1854     size: 4in 6in;

  1855   }

  1857   @media (max-width: 6in) {

  1858     @page {

  1859       size: letter;

  1860     }

  1861   }

  1862   </pre>

  1863   <p>The second <code>size</code> declaration is ignored, i.e. the specified value

  1864   of the <code>size</code> property is <code>4in 6in</code>.

  1865 </div>

  1867 <table class="page-sizes">

  1868 <tr>

  1869 <th>Value</th>

  1870 <th>Description</th>

  1871 </tr>

  1872 <tr>

  1873 <td>auto</td>

  1874 <td>The page box will be set to a size and orientation chosen by the UA. In the

  1875 usual case, the page box size and orientation is chosen to match the target

  1876 media sheet.</td>

  1877 </tr>

  1878 <tr>

  1879 <td>landscape</td>

  1880 <td>Specifies that the page's content be printed in landscape orientation. The

  1881 longer sides of the page box are horizontal. If a <span class="css">'&lt;page-size&gt;'</span> is not specified, the size of the page sheet

  1882 is chosen by the UA.</td>

  1883 </tr>

  1884 <tr>

  1885 <td>portrait</td>

  1886 <td>Specifies that the page's content be printed in portrait orientation. The

  1887 shorter sides of the page box are horizontal. If a <span class="css">'&lt;page-size&gt;'</span> is not specified, the size of the page sheet

  1888 is chosen by the UA.</td>

  1889 </tr>

  1890 <tr>

  1891 <td>&lt;length&gt;</td>

  1892 <td>The page box will be set to the given absolute dimension(s). If only one length

  1893 value is specified, it sets both the width and height of the page box (i.e.,

  1894 the box is a square). If two length values are specified, the first establishes

  1895 the page box width, and the second the page box height. Values in units of

  1896 <span class="css">'em'</span> and <span class="css">'ex'</span> refer to the

  1897 page context's font. Negative lengths are illegal.</td>

  1898 </tr>

  1899 <tr>

  1900 <td>&lt;page-size&gt;</td>

  1901 <td>A page size can be specified using one of the following media names. This is

  1902 the equivalent of specifying the <span class="css">'&lt;page-size&gt;'</span>

  1903 using length values. The definition of the the media names comes from

  1904 <cite>Media Standardized Names</cite> [[!PWGMSN]].

  1906 <dl>

  1908 <dt>A5</dt>

  1909 <dd>Equivalent to the size of ISO A5 media: 148mm wide and 210 mm high.</dd>

  1911 <dt>A4</dt>

  1912 <dd>Equivalent to the size of ISO A4 media: 210 mm wide and 297 mm high.</dd>

  1914 <dt>A3</dt>

  1915 <dd>Equivalent to the size of ISO A3 media: 297mm wide and 420mm high.</dd>

  1917 <dt>B5</dt>

  1918 <dd>Equivalent to the size of ISO B5 media: 176mm wide by 250mm high.</dd>

  1920 <dt>B4</dt>

  1921 <dd>Equivalent to the size of ISO B4 media: 250mm wide by 353mm high.</dd>

  1923 <dt>letter</dt>

  1924 <dd>Equivalent to the size of North American letter media: 8.5 inches wide and 11

  1925 inches high</dd>

  1927 <dt>legal</dt>

  1928 <dd>Equivalent to the size of North American legal: 8.5 inches wide by 14 inches

  1929 high.</dd>

  1931 <dt>ledger</dt>

  1932 <dd>Equivalent to the size of North American ledger: 11 inches wide by 17 inches

  1933 high.</dd>

  1934 </dl></td>

  1935 </tr>

  1936 </table>

  1938 <p>The '&lt;page-size&gt;' names can be used in conjunction with 'landscape' or

  1939 'portrait' to indicate both size and orientation.</p>

  1941 <h4>Some examples:</h4>

  1943 <div class="example">

  1944 <pre>

  1945 @page {

  1946 size: A4 landscape;

  1947 }

  1948 </pre>

  1950 <p>The above example sets the width of the page box to be 297mm and the height to

  1951 be 210mm. The page box in this example should be rendered on a page sheet size

  1952 of 210 mm by 297 mm.</p>

  1953 </div>

  1955 <div class="example">

  1957 <p>In the following example, the outer edges of the page box will align with the

  1958 page. The percentage value on the <span class="property">'margin'</span>

  1959 property is relative to the page size so if the page sheet dimensions are 210mm

  1960 x 297mm (i.e., A4), the margins are 21mm and 29.7mm. Assuming there are no page

  1961 borders or padding set in the UA default style sheet, the resulting page area

  1962 is 189mm by 367.3mm (210mm-21mm by 297mm-29.7mm).</p>

  1963 <pre>

  1964 @page {

  1965 size: auto;/* auto is the initial value */

  1966 margin: 10%;

  1967 }

  1968 </pre>

  1969 </div>

  1971 <div class="example">

  1972 <pre>

  1973 @page {

  1974 size: 8.5in 11in;/* width height */

  1975 }

  1976 </pre>

  1978 <p>The above example sets the width of the page box to be 8.5 inches and the

  1979 height to be 11 inches. This indicates that the page sheet size should be

  1980 8.5"x11" and the orientation 'portrait'.</p>

  1981 </div>

  1983 <h4 id="page-size-media-query">Media Queries</h4>

  1985 <p>This section is informative.</p>

  1987 <p>By using Media Queries [[MEDIAQ]], one style sheet can express different

  1988 stylistic preferences for different page sizes. Consider this example:</p>

  1990 <div class="example" style="font-size: 10pt;">

  1991 <pre>

  1992  /* style sheet for "A4" printing */

  1993  @media print and (width: 21cm) and (height: 29.7cm) {

  1994     @page {

  1995        margin: 3cm;

  1996     }

  1997  }

  1999  /* style sheet for "letter" printing */

  2000  @media print and (width: 8.5in) and (height: 11in) {

  2001     @page {

  2002         margin: 1in;

  2003     }

  2004  }

  2005 </pre>

  2006 </div>

  2008 <p>In the example above, "A4" sheets are given a "3cm" page margin, and "letter"

  2009 sheets are given a "1in" page margin.</p>

  2011 <h3 id="renderingpages">Rendering page boxes that do not fit a page sheet</h3>

  2013 <p>If a page box does not match the target page sheet dimensions, the user agent

  2014 should do one of the following (in order of preference):</p>

  2016 <ol>

  2017   <li>Render the page box at the indicated size on a larger page sheet.</li>

  2018   <li>Rotate the page box 90° if this will make the page box fit the page sheet.</li>

  2019   <li>Scale the page box to fit the page sheet. (The aspect ratio of the page box

  2020   <em class="RFC2119">should</em> be preserved.)</li>

  2021   <li>Reformat the page contents, including 'spilling' onto other page sheets.</li>

  2022   <li>Clip overflowed content (least preferred).</li>

  2023 </ol>

  2025 <p>The user agent <em class="RFC2119">MAY</em> wish to consult the user before

  2026 performing these operations.</p>

  2028 <h3 id="positioning-page-box">Positioning the page box on the sheet</h3>

  2030 <p>When the page box is smaller than the page size, the user agent <em class="RFC2119">SHOULD</em> either:</p>

  2032 <ul>

  2033   <li>center the page box on the sheet since this will align double-sided pages

  2034   and avoid accidental loss of information that is printed near the edge of the

  2035   sheet; or</li>

  2036   <li>position the page box in the upper left corner of the page sheet, as this

  2037   may minimize media consumption.</li>

  2038 </ul>

  2040 <p>The user agent <em class="RFC2119">MAY</em> wish to consult the user in this

  2041 regard.</p><!-- "Page selector and page context" -->

  2043 <h2 id="page-breaks">

  2044     <a id="pg-br-before-after"></a>

  2045     <a id="page-break-before"></a>

  2046     <a id="page-break-after"></a>

  2047     <a id="page-break-inside"></a>

  2048     <a id="breaks-inside"></a>

  2049     <a id="orphans"></a>

  2050     <a id="widows"></a>

  2051     <a id="allowed-pg-brk"></a>

  2052     <a id="brk-btw-blocks"></a>

  2053     <a id="brk-btw-lines"></a>

  2054     <a id="brk-end-block"></a>

  2055     <a id="forced-pg-brk"></a>

  2056     <a id="best-pg-brk"></a>

  2057     Page Breaks

  2058 </h2>

  2060 <p>

  2061   The CSS Fragmentation Module [[!CSS3-BREAK]] module

  2062   defines how and where CSS boxes

  2063   can be <i>fragmented</i>, including across page breaks.

  2064   It defines a few properties that indicate where the user agent

  2065   <em class="RFC2119">MAY</em> or <em class="RFC2119">MUST</em> break pages,

  2066   and on what page (left or right) the subsequent content resumes.

  2067   Each page break ends layout in the current <a href="#page-box">page box</a>

  2068   and causes remaining pieces of the document tree to be laid out

  2069   in a new page box.

  2070 </p>

  2072 <h3 id="using-named-pages">Using named pages: 'page'</h3>

  2073 <table class="propdef" summary="property definition">

  2074   <tr>

  2075     <th>Name:

  2076     <td><dfn id="page">page</dfn>

  2077   <tr>

  2078     <th>Value:

  2079     <td>auto | &lt;identifier&gt;

  2080   <tr>

  2081     <th>Initial:

  2082     <td>auto

  2083   <tr>

  2084     <th>Applies to:

  2085     <td>boxes that create <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class 1</a> break points

  2086   <tr>

  2087     <th>Inherited:

  2088     <td>no (but see prose)

  2089   <tr>

  2090     <th>Percentages:

  2091     <td>N/A

  2092   <tr>

  2093     <th>Media:

  2094     <td>paged

  2095   <tr>

  2096     <th>Computed value:

  2097     <td>specified value

  2098 </table>

  2100 <p>

  2101   The 'page' property is used to specify a particular type of page (called a <dfn>named page</dfn>)

  2102   on which an element <em class="RFC2119">MUST</em> be displayed.

  2103   If necessary, a <i>forced page break</i> is introduced

  2104   and a new page generated of the specified type.

  2106 <p class="note">

  2107   This page can be styled by using the same type name

  2108   in a <a href="#page-selectors">page selector</a>.

  2110 <p>

  2111   Page type names are case-sensitive identifiers.

  2112   However the ''auto'' value, being a CSS keyword, is

  2113   <a href="http://www.w3.org/TR/CSS21/syndata.html#characters">ASCII case-insensitive</a>.

  2115 <p>

  2116   The 'page' property does not inherit.

  2117   However, if the 'page' value on an element is ''auto'',

  2118   then its used value is the value specified

  2119   on its nearest ancestor with a non-auto value.

  2120   When specified on the root element,

  2121   the used value for ''auto'' is the empty string.

  2123   <!-- See http://www.w3.org/TR/2007/WD-css3-gcpm-20070504/#named3 -->

  2125 <p>

  2126   Because a previous version of this specification indicated that the 'page' property is inherited,

  2127   an implementation that inherits the 'page' property

  2128   and treats ''auto'' as always naming the empty string

  2129   remains conformant to CSS3 Paged Media.

  2130   Therefore authors should not explicitly specify the ''auto'' value

  2131   on a descendant of an element with a non-''auto'' value,

  2132   as the resulting behavior will be unpredictable.

  2134 <p>

  2135   The 'page' property works as follows:

  2137 <ol>

  2139   <li>

  2140     First, any ''auto'' values are resolved against non-''auto'' ancestors

  2141     (as specified above).

  2143   <li>

  2144     Next,

  2145     a <dfn>start 'page' value</dfn> and <dfn>end 'page' value</dfn>

  2146     is determined for each box

  2147     as the value (if any) propagated from its first or last child (respectively),

  2148     else the used value on the box itself.

  2149     A child propagates its own <i title="start page value">start</i> or <i>end 'page' value</i>

  2150     if and only if the 'page' property applies to it.

  2152   <li>

  2153     The first printed page’s type is the <i>start 'page' value</i> of the root.

  2155   <li>

  2156     If for any two boxes meeting at a <a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class 1</a> break point,

  2157     the <i>end 'page' value</i> of the box preceding the break

  2158     and <i>start 'page' value</i> of the box succeeding the break

  2159     do not match,

  2160     then a page break is forced between the two boxes,

  2161     and content after the break resumes on a page box of the named type.

  2162 </ol>

  2164 <p class="note">

  2165   Essentially, the two 'page' values compared are those from the deepest boxes

  2166   meeting at the class 1 break point,

  2167   ignoring any subtrees rooted by boxes to which the 'page' property does not apply.

  2169 <p>See [[!CSS3-BREAK]] for additional details on page breaks.

  2171 <div class="example">

  2173 <p>In this example, the two tables are rendered on landscape pages (indeed, on the

  2174 same page, if they fit). The page type "narrow" is used for the &lt;p&gt; after

  2175 the second table, as the page properties for the table element are no longer in

  2176 effect:</p>

  2177 <pre>

  2178 @page narrow { size: 9cm 18cm }

  2179 @page rotated { size: landscape }

  2180 div { page: narrow }

  2181 table { page: rotated }

  2182 </pre>with this document:

  2183 <pre>

  2184 &lt;div&gt;

  2185 &lt;table&gt;...&lt;/table&gt;

  2186 &lt;table&gt;...&lt;/table&gt;

  2187 &lt;p&gt;This text is rendered on a 'narrow' page&lt;/p&gt;

  2188 &lt;/div&gt;

  2189 </pre>

  2190 </div>

  2192 <div class="example">

  2193   <p>In Japanese documents, sometimes different parts of a single document

  2194   will have different <i lang="ja-Latn">kihon hanmen</i>. [[JLREQ]]

  2195   The 'page' property, together with ''@page'' rules specifying different page widths,

  2196   can accomodate this type of layout:

  2197   <pre>

  2198 &lt;!DOCTYPE html>

  2199 &lt;html lang="ja">

  2200   &lt;style>

  2201     html   { writing-mode: vertical-rl;

  2202              line-height: 1.6; }

  2203     .main  { page: main;

  2204              columns: 2; column-gap: 1rem; }

  2205     .index { page: index;

  2206              columns: 3; column-gap: 1rem; }

  2207     @page       { margin: auto;    /* center kihon hanmen on page */

  2208                   width:  40rem; } /* 1.6 &times; 25 lines        */

  2209     @page main  { height: 61rem; } /* 2 &times; 30 chars + 1 &times; gap */

  2210     @page index { height: 62rem; } /* 3 &times; 20 chars + 2 &times; gap */

  2211   &lt;/style>

  2212   &lt;section class="main"> ... &lt;/section>

  2213   &lt;section class="index"> ... &lt;/section>

  2214 &lt;/html>

  2215 </pre>

  2216 </div>

  2219 <h2 id="image-properties">Image Properties</h2>

  2221 <p class="note">This section has been moved to [[CSS3-IMAGES]].</p>

  2223 <h2 class="no-num" id="properties-list">Appendix A: Applicable CSS2.1 Properties</h2>

  2225 <h3 class="no-num">Properties that apply within the page context</h3>

  2227 <p>The following CSS 2.1 [[!CSS21]] properties apply to the page box.

  2228 If a conforming user agent supports any of these properties on block

  2229 boxes, then it must also support that property for the page box.</p>

  2231 <table class="property-list">

  2232   <tbody>

  2233     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#direction">bidi properties</a>

  2234         <td>direction

  2235   <tbody>

  2236     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a>

  2237         <td>background-color

  2238     <tr><td>background-image

  2239     <tr><td>background-repeat

  2240     <tr><td>background-attachment

  2241     <tr><td>background-position

  2242     <tr><td>background

  2243   <tbody>

  2244     <tr><td rowspan="20"><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a>

  2245         <td>border-top-width

  2246     <tr><td>border-right-width

  2247     <tr><td>border-bottom-width

  2248     <tr><td>border-left-width

  2249     <tr><td>border-width

  2250     <tr><td>border-top-color

  2251     <tr><td>border-right-color

  2252     <tr><td>border-bottom-color

  2253     <tr><td>border-left-color

  2254     <tr><td>border-color

  2255     <tr><td>border-top-style

  2256     <tr><td>border-right-style

  2257     <tr><td>border-bottom-style

  2258     <tr><td>border-left-style

  2259     <tr><td>border-short-style

  2260     <tr><td>border-top

  2261     <tr><td>border-right

  2262     <tr><td>border-bottom

  2263     <tr><td>border-left

  2264     <tr><td>border

  2265   <tbody>

  2266     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a>

  2267         <td>counter-reset

  2268     <tr><td>counter-increment

  2269   <tbody>

  2270     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a>

  2271   <tbody>

  2272     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a>

  2273         <td>font-family

  2274     <tr><td>font-size

  2275     <tr><td>font-style

  2276     <tr><td>font-variant

  2277     <tr><td>font-weight

  2278     <tr><td>font

  2279   <tbody>

  2280     <tr><td rowspan="3"><a href="http://www.w3.org/TR/CSS21/visudet.html#the-height-property">height</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-heights">properties</a>

  2281         <td>height

  2282     <tr><td>min-height

  2283     <tr><td>max-height

  2284   <tbody>

  2285     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a>

  2286   <tbody>

  2287     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a>

  2288         <td>margin-top

  2289     <tr><td>margin-right

  2290     <tr><td>margin-bottom

  2291     <tr><td>margin-left

  2292     <tr><td>margin

  2293   <tbody>

  2294     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  2295         <td>outline-width

  2296     <tr><td>outline-style

  2297     <tr><td>outline-color

  2298     <tr><td>outline

  2299   <tbody>

  2300     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a>

  2301         <td>padding-top

  2302     <tr><td>padding-right

  2303     <tr><td>padding-bottom

  2304     <tr><td>padding-left

  2305     <tr><td>padding

  2306   <tbody>

  2307     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  2308   <tbody>

  2309     <tr><td rowspan="8"><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a>

  2310         <td>direction

  2311     <tr><td>letter-spacing

  2312     <tr><td>text-align

  2313     <tr><td>text-decoration

  2314     <tr><td>text-indent

  2315     <tr><td>text-transform

  2316     <tr><td>white-space

  2317     <tr><td>word-spacing

  2318   <tbody>

  2319     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a>

  2320   <tbody>

  2321     <tr><td rowspan="3"><a href="http://www.w3.org/TR/CSS21/visudet.html#the-width-property">width</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-widths">properties</a>

  2322         <td>width

  2323     <tr><td>min-width

  2324     <tr><td>max-width

  2325 </table>

  2327 <p>Properties that apply to the page-margin boxes can also be set within

  2328 the page context: if inheritable or explicitly inherited (with the

  2329 <code>inherit</code> keyword in the margin context), they will inherit

  2330 to the page-margin boxes.</p>

  2332 <h3 class="no-num">Properties that apply within the margin contexts</h3>

  2334 <p>The following CSS 2.1 [[!CSS21]] properties apply to page-margin boxes.

  2335 If a conforming user agents supports any of these properties on block

  2336 boxes, then it must also support that property for page-margin boxes (except

  2337 for <code>z-index</code>, which is optional for page-margin boxes).</p>

  2339 <table class="property-list">

  2340   <tbody>

  2341     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#direction">bidi properties</a>

  2342         <td>direction

  2343     <tr><td>unicode-bidi

  2344   <tbody>

  2345     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a>

  2346         <td>background-color

  2347     <tr><td>background-image

  2348     <tr><td>background-repeat

  2349     <tr><td>background-attachment

  2350     <tr><td>background-position

  2351     <tr><td>background

  2352   <tbody>

  2353     <tr><td rowspan="20"><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a>

  2354         <td>border-top-width

  2355     <tr><td>border-right-width

  2356     <tr><td>border-bottom-width

  2357     <tr><td>border-left-width

  2358     <tr><td>border-width

  2359     <tr><td>border-top-color

  2360     <tr><td>border-right-color

  2361     <tr><td>border-bottom-color

  2362     <tr><td>border-left-color

  2363     <tr><td>border-color

  2364     <tr><td>border-top-style

  2365     <tr><td>border-right-style

  2366     <tr><td>border-bottom-style

  2367     <tr><td>border-left-style

  2368     <tr><td>border-short-style

  2369     <tr><td>border-top

  2370     <tr><td>border-right

  2371     <tr><td>border-bottom

  2372     <tr><td>border-left

  2373     <tr><td>border

  2374   <tbody>

  2375     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a>

  2376         <td>counter-reset

  2377     <tr><td>counter-increment

  2378   <tbody>

  2379     <tr><td colspan="2"><a href="">content</a>

  2380   <tbody>

  2381     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a>

  2382   <tbody>

  2383     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a>

  2384         <td>font-family

  2385     <tr><td>font-size

  2386     <tr><td>font-style

  2387     <tr><td>font-variant

  2388     <tr><td>font-weight

  2389     <tr><td>font

  2390   <tbody>

  2391     <tr><td rowspan="3"><a href="http://www.w3.org/TR/CSS21/visudet.html#the-height-property">height</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-heights">properties</a>

  2392         <td>height

  2393     <tr><td>min-height

  2394     <tr><td>max-height

  2395   <tbody>

  2396     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a>

  2397   <tbody>

  2398     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a>

  2399         <td>margin-top

  2400     <tr><td>margin-right

  2401     <tr><td>margin-bottom

  2402     <tr><td>margin-left

  2403     <tr><td>margin

  2404   <tbody>

  2405     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  2406         <td>outline-width

  2407     <tr><td>outline-style

  2408     <tr><td>outline-color

  2409     <tr><td>outline

  2410   <tbody>

  2411     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#overflow">overflow</a>

  2412   <tbody>

  2413     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a>

  2414         <td>padding-top

  2415     <tr><td>padding-right

  2416     <tr><td>padding-bottom

  2417     <tr><td>padding-left

  2418     <tr><td>padding

  2419   <tbody>

  2420     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  2421   <tbody>

  2422     <tr><td rowspan="7"><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a>

  2423         <td>letter-spacing

  2424     <tr><td>text-align

  2425     <tr><td>text-decoration

  2426     <tr><td>text-indent

  2427     <tr><td>text-transform

  2428     <tr><td>white-space

  2429     <tr><td>word-spacing

  2430   <tbody>

  2431     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">vertical-align</a>

  2432   <tbody>

  2433     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a>

  2434   <tbody>

  2435     <tr><td rowspan="3"><a href="http://www.w3.org/TR/CSS21/visudet.html#the-width-property">width</a> <a href="http://www.w3.org/TR/CSS21/visudet.html#min-max-widths">properties</a>

  2436         <td>width

  2437     <tr><td>min-width

  2438     <tr><td>max-width

  2439   <tbody>

  2440     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#z-index">z-index</a>

  2441 </table>

  2443 <h2 class="no-num" id="transfer-possibilities">Appendix B: Transfer Possibilities</h2>

  2445 <p>Often, but not always, the page box has a one-to-one correspondence to the

  2446 physical surface onto which the document is ultimately rendered. The CSS3 page

  2447 model specifies formatting within the page box, but it is the user agent's

  2448 responsibility to transfer the page box to the sheet. Some user agent transfer

  2449 possibilities that are not addressed by CSS3 include:</p>

  2451 <ul id="complex-usecases">

  2452   <li>Transferring one page box to one sheet (e.g. single-sided printing);</li>

  2453   <li>Transferring two page boxes to the front and back surfaces of the same

  2454   sheet (e.g. double-sided printing);</li>

  2455   <li>Transferring N (small) page boxes to one sheet (called "N-up");</li>

  2456   <li>Transferring one (large) page box to N x M sheets (called "tiling");</li>

  2457   <li>Creating signatures. A <dfn>signature</dfn> is a group of pages printed on

  2458   a sheet, which, when folded and trimmed like a book, appear in their proper

  2459   sequence;</li>

  2460   <li>Printing one document to multiple output trays;</li>

  2461   <li>Generating files containing print instructions.</li>

  2462 </ul>

  2464 <h2 class="no-num" id="changes">Changes</h2>

  2466 <p>

  2467   Changes since the <a href="http://www.w3.org/TR/2006/WD-css3-page-20061010/">10 October 2006 Working Draft</a> are:

  2468 </p>

  2470 <ul>

  2471   <li>The first printed page can be <a href="#using-named-pages">named</a>.

  2473   <li>The '':blank'' <a href="#pseudo-classes">pseudo-class</a> was imported

  2474     from the <a href="http://dev.w3.org/csswg/css3-gcpm/">Generated Content for Paged Media</a> module.

  2476   <li>''@page'' rules can now take multiple comma separated selectors,

  2477     each selector can have multiple pseudo-classes.

  2479     <div class="example">

  2480       <pre>@page :first, :blank { @bottom-center { content: none } }</pre>

  2481       <pre>@page :first:left { @bottom-left { content: none } }</pre>

  2482     </div>

  2484   <li>Margin boxes are renamed <a href="#margin-boxes">page-margin boxes</a>,

  2485     to avoid confusion with the margin area of each box.

  2487   <li>The <a href="#variable-sizing">Variable Dimension</a>

  2488     layout rules for page-margin boxes have been much simplified

  2489     to not require quadratic optimization.

  2491   <li>The relative <a href="#painting">painting order</a>

  2492     of page-margin boxes and page content has changed.

  2494   <li>The description of page breaks and definition of related properties

  2495     (except for the 'page' property)

  2496     have been moved to the CSS Fragmentation Module. [[!CSS3-BREAK]]

  2498   <li>The 'fit' and 'fit-position' properties

  2499     are renamed to 'object-fit' and 'object-position',

  2500     redefined to enable additional use cases,

  2501     and moved to the CSS3 Image Values and Replaced Content module.

  2502     [[CSS3-IMAGES]]

  2504   <li>Many miscellaneous clarifications

  2505     and editorial improvements have been incorporated.

  2507 </ul>

  2510 <h2 class="no-num" id="references">References</h2>

  2512 <h3 class="no-num" id="normative-references">Normative References</h3><!--normative-->

  2514 <h3 class="no-num" id="informative-references">Informative References</h3><!--informative-->

  2515 </div>

  2516 </div>

  2517 </body>

  2518 </html>

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