drafts: css3-page/Overview.src.html@76b534d18604

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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">

   823       Given the syntax of page seletors, <var>f</var> can only ever be 0 or 1.

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

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

   826 </ul>

   828 <p>

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

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

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

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

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

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

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

   837 <p>

   838   Due to storage limitations,

   839   implementations may have limitations on

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

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

   842   and not overflow.

   844 <p class="note">

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

   846   has its own specificity.

   848 <p class="note">

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

   850   and do increase specificity.

   852 <div class="example">

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

   855 <pre>

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

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

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

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

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

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

   862 </pre>

   863 </div>

   865 <div class="example">

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

   868 <pre>

   869 @page {

   870   margin-left: 3cm;

   871 }

   873 @page :left {

   874   margin-left: 4cm;

   875 }

   876 </pre>

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

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

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

   881 </div>

   883 <div class="example">

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

   885 rule.

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

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

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

   889 <pre>

   890 @page :first {

   891   color: green;

   893   @top-left {

   894     content: "foo";

   895     color: blue;

   896   }

   897   @top-right {

   898     content: "bar";

   899   }

   900 }

   902 @page { color: red;

   903   @top-center {

   904     content: "Page " counter(page);

   905   }

   906 }

   907 </pre>

   908 </div>

   910 <div class="example">

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

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

   914 <pre>

   915 @page { margin: 25mm;}

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

   917 </pre>

   918 </div>

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

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

   923   like pseudo-elements, can contain generated content.

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

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

   927   such as the page number or document title.

   929   <div class="example">

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

   931     in documents with a predominately horizontal writing direction

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

   933     for documents with a predominately vertical writing direction.

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

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

   936     page-margin boxes.

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

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

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

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

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

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

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

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

   946     at the top of the page could use the

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

   948     page-margin boxes as the page footer.

   949     The design of a vertically written document could use

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

   951   </div>

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

   954   and are independent of page orientation,

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

   956   in both portrait and landscape orientation.

   957   The various page-margin boxes are defined

   958   and illustrated in the diagram below:

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

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

   962     <thead>

   963       <tr>

   964         <th>Box</th>

   965         <th>Description</th>

   966         <th>Placement</th>

   967       </tr>

   968     </thead>

   969     <tbody>

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

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

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

   973         page box</td>

   974         <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"

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

   976       </tr>

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

   978         <th>top-left</th>

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

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

   981         <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"

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

   983       </tr>

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

   985         <th>top-center</th>

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

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

   988         page-margin boxes</td>

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

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

   991       </tr>

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

   993         <th>top-right</th>

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

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

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

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

   998       </tr>

   999       <tr>

  1000         <th id="top-right-corner-box-def">top-right-corner</th>

  1001         <td>a fixed-size box defined by the intersection of the top and right margins of

  1002         the page box</td>

  1003         <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"

  1004         height="47" width="181"></td>

  1005       </tr>

  1006       <tr id="left-margin-boxes-def">

  1007         <th id="left-top-box-def">left-top</th>

  1008         <td>a variable-height box filling the left page margin between the top-left-corner

  1009         and left-middle page-margin boxes</td>

  1010         <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"

  1011         height="226" width="181"></td>

  1012       </tr>

  1013       <tr id="left-middle-box-def">

  1014         <th>left-middle</th>

  1015         <td>a variable-height box centered vertically between the page's top and bottom

  1016         border edges and filling the left page margin between the left-top and

  1017         left-bottom page-margin boxes</td>

  1018       </tr>

  1019       <tr id="left-bottom-box-def">

  1020         <th>left-bottom</th>

  1021         <td>a variable-height box filling the left page margin between the left-middle and

  1022         bottom-left-corner page-margin boxes</td>

  1023       </tr>

  1024       <tr id="right-margin-boxes-def">

  1025         <th id="right-top-box-def">right-top</th>

  1026         <td>a variable-height box filling the right page margin between the

  1027         top-right-corner and right-middle page-margin boxes</td>

  1028         <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"

  1029         height="226" width="181"></td>

  1030       </tr>

  1031       <tr id="right-middle-box-def">

  1032         <th>right-middle</th>

  1033         <td>a variable-height box centered vertically between the page's top and bottom

  1034         border edges and filling the right page margin between the right-top and

  1035         right-bottom page-margin boxes</td>

  1036       </tr>

  1037       <tr id="right-bottom-box-def">

  1038         <th>right-bottom</th>

  1039         <td>a variable-height box filling the right page margin between the right-middle

  1040         and bottom-right-corner page-margin boxes</td>

  1041       </tr>

  1042       <tr id="bottom-margin-boxes-def">

  1043         <th id="bottom-left-corner-box-def">bottom-left-corner</th>

  1044         <td>a fixed-size box defined by the intersection of the bottom and left margins of

  1045         the page box</td>

  1046         <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"

  1047         height="48" width="181"></td>

  1048       </tr>

  1049       <tr id="bottom-left-box-def">

  1050         <th>bottom-left</th>

  1051         <td>a variable-width box filling the bottom page margin between the

  1052         bottom-left-corner and bottom-center page-margin boxes</td>

  1053         <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"

  1054         height="48" width="181"></td>

  1055       </tr>

  1056       <tr id="bottom-center-box-def">

  1057         <th>bottom-center</th>

  1058         <td>a variable-width box centered horizontally between the page's left and right

  1059         border edges and filling the bottom page margin between the bottom-left and

  1060         bottom-right page-margin boxes</td>

  1061         <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"

  1062         height="48" width="181"></td>

  1063       </tr>

  1064       <tr id="bottom-right-box-def">

  1065         <th>bottom-right</th>

  1066         <td>a variable-width box filling the bottom page margin between the bottom-center

  1067         and bottom-right-corner page-margin boxes</td>

  1068         <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"

  1069         height="48" width="181"></td>

  1070       </tr>

  1071       <tr id="bottom-right-corner-box-def">

  1072         <th>bottom-right-corner</th>

  1073         <td>a fixed-size box defined by the intersection of the bottom and right margins of

  1074         the page box</td>

  1075         <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"

  1076         height="48" width="181"></td>

  1077       </tr>

  1078     </tbody>

  1079   </table>

  1081 <h3 id="margin-at-rules">At-rules for page-margin boxes</h3>

  1083 <p>Page-margin boxes are created by

  1084 <a href="#margin-at-rules">margin at-rules</a>

  1085 inside the <a href="#page-context">page context</a>.

  1086 These rules should come after any declarations in the page context as legacy

  1087 clients may not handle declarations after margin at-rules correctly.</p>

  1089 <p>A <dfn id="margin-at-rule">margin at-rule</dfn> consists of an

  1090 <a href="#specializatons-of-ATKEYWORD">ATKEYWORD</a>

  1091 that identifies the page-margin box

  1092 (e.g. <span class="css">'@top-left'</span>) and a block of declarations (said

  1093 to be in the <dfn id="margin-context">margin context</dfn>).</p>

  1095 <div class="example">

  1097 <p>The following style sheet establishes a page header containing the title

  1098 ("Hamlet") on the left side and the page number, preceded by "Page ", on the

  1099 right side:</p>

  1100 <pre>

  1101 @page {

  1102   size: 8.5in 11in;

  1103   margin: 10%;

  1105   @top-left {

  1106     content: "Hamlet";

  1107   }

  1108   @top-right {

  1109     content: "Page " counter(page);

  1110   }

  1111 }

  1112 </pre>

  1113 </div>

  1116 <h3 id="populating-margin-boxes">Populating page-margin boxes</h3>

  1118 <p>As with the '':before'' and '':after'' pseudo-elements,

  1119 a specified 'content' of ''normal'' on a page-margin box computes to ''none'',

  1120 and the page-margin box is <dfn>generated</dfn>

  1121 if and only if the computed value

  1122 of its 'content' property is not 'none'.

  1123 Otherwise it behaves as if it had ''display: none''.

  1125 <div class="example">

  1126 <p>The following style sheet creates a green box in each corner of the page

  1127 except the bottom-left corner.</p>

  1128 <pre>

  1129   @page {

  1130     @top-left-corner { content: " "; border: solid green; }

  1131     @top-right-corner { content: url(foo.png); border: solid green; }

  1132     @bottom-right-corner { content: counter(page); border: solid green; }

  1133     @bottom-left-corner { content: normal; border: solid green; }

  1134   }

  1135 </pre>

  1136 </div>

  1138 <h3 id="margin-dimension">Computing Page-margin Box Dimensions</h3>

  1140 <p>The width and height of each page-margin box is determined by the rules

  1141 below. These rules define the equivalent of CSS2.1 Sections 10.3 and

  1142 10.6 for page-margin boxes.</p>

  1144 <p>The rules for applying 'min-height', 'max-height', 'min-width', and

  1145 'max-width' [[!CSS21]] do apply to page-margin boxes and may imply

  1146 a recalculation of the width, height, and/or margins

  1147 if the dimensions resulting from the specified 'width' or 'height'

  1148 violate their constraints.

  1149 If the UA does not support the 'min-height' or 'min-width' properties

  1150 then it must behave as if 'min-height' and 'min-width' were always zero.

  1152 <h4 id="margin-box-terms"><a id="max-margin-dimension"></a>Page-Margin Box Layout Terminology</h4>

  1154   <p>In addition to the box model definitions in CSS2.1 [[!CSS21]],

  1155   and the sizing terms in CSS Intrinsic Sizing [[!CSS3-SIZING]],

  1156   the following terms are defined for use

  1157   in the subsequent page-margin box calculations:

  1159   <dl>

  1161     <dt><dfn>available width</dfn></dt>

  1162     <dd>The sum of the page’s

  1163       left border width, left padding, <a href="#page-box">page area</a> width,

  1164       right padding, and right border width.

  1165       In other words, it is the distance between

  1166       the <a href="#page-box">page box</a>’s left right border edges.

  1167       This quantity is used  when calculating dimensions

  1168       of the top and bottom page-margin boxes.

  1170     <dt><dfn>available height</dfn></dt>

  1171     <dd>The sum of the page’s

  1172       top border width, top padding, <a href="#page-box">page area</a> height,

  1173       bottom padding, and bottom border width.

  1174       In other words, it is the distance between

  1175       the <a href="#page-box">page box</a>’s top bottom border edges.

  1176       This quantity is used when calculating dimensions

  1177       of the left and right page-margin boxes.

  1179     <dt><dfn>outer width</dfn></dt>

  1180     <dd>The width of the

  1181       <a href="http://www.w3.org/TR/CSS21/box.html#outer-edge">outer edge</a>,

  1182       as defined in [[!CSS21]].

  1184     <dt><dfn>outer min width</dfn></dt>

  1185     <dd>Like the <i>outer width</i>, except that

  1186     <a href="http://www.w3.org/TR/css3-sizing/#min-content">''min-content''</a>

  1187     is used when the width is ''auto''.

  1189     <dt><dfn>outer max width</dfn></dt>

  1190     <dd>Like the <i>outer width</i>, except that

  1191     <a href="http://www.w3.org/TR/css3-sizing/#max-content">''max-content''</a>

  1192     is used when 'width' is ''auto''.

  1193   </dl>

  1195   <p>The <dfn>containing block</dfn> for a corner page-margin box is

  1196   the rectangle defined by the intersection of the two page margins meeting at that corner.

  1198   <p>For all other page-margin boxes,

  1199   the <dfn>containing block</dfn> is the rectangle

  1200   formed by the encapsulating page margin minus the containing blocks of the

  1201   adjacent corners' page-margin boxes.

  1202   This means that the size of this containing block is given

  1203   in one dimension by the used page margin and in the other dimension

  1204   by the <i>available width</i>

  1205   (for top and bottom page-margin boxes) or

  1206   <i>available height</i>

  1207   (for left and right page-margin boxes).</p>

  1209 <h4 id="variable-sizing">

  1210 Page-Margin Box Variable Dimension Computation Rules</h4>

  1212 <p>The following rules apply to 'top-left', 'top-center' and 'top-right'

  1213 page-margin boxes,

  1214 which are referred to as A, B, and C, respectively, in this section.</p>

  1216 <h5 id="variable-auto-margins">Margins</h5>

  1218 <p>If the 'margin-left' or 'margin-right' property of any of the three boxes

  1219 computes to ''auto'', the used value is zero.</p>

  1221 <h5 id="variable-auto-sizing">Resolving ''auto'' widths</h5>

  1223 <p>The following algorithm determines the used width of each box.

  1224 For this purpose, boxes that are not <i>generated</i>

  1225 are assumed to have a 'width' and an <i>outer width</i> of zero.

  1226 </p>

  1228 <p class="note">

  1229 Note: The high-level goals are (in order of priority) to center the middle

  1230 box (B) if it is generated, to minimize overflow and overlap, and to

  1231 distribute space proportionally to the amount of content.</p>

  1233   <p>If the middle box (B) is not <i>generated</i>,

  1234   distribute the <i>available width</i> to A and C as follows:

  1236   <ul>

  1237     <li>

  1238       If only one box has 'width: auto',

  1239       its used width is resolved so that

  1240       the sum of the <i>outer width</i>s equals <i>available width</i>.

  1241     </li>

  1243     <li id="flex-fit">

  1244       If A and C both have 'width: auto', distribute the space to each box as follows:

  1245       <ol>

  1246         <li>If the sum of the outer <i>max-content widths</i> is less than the <i>available width</i>,

  1247             call that difference the <i>flex space</i>.

  1248             Calculate each box's <i>flex factor</i> as proportional to

  1249             its outer <i>max-content width</i>,

  1250             and set its used outer width to:

  1251               <pre><i>max-content width</i> + <i>flex space</i> × <i>flex factor</i> ÷ ∑<i>flex factors</i></pre>

  1252         <li>Otherwise if the sum of the outer <i>min-content widths</i> is less than the <i>available width</i>,

  1253             call that difference the <i>flex space</i>

  1254             calculate each box's <i>flex factor</i> as proportional to

  1255             its <i>max-content</i> minus <i>min-content</i>,

  1256             and set its used outer width to:

  1257               <pre><i>min-content width</i> + <i>flex space</i> × <i>flex factor</i> ÷ ∑<i>flex factors</i></pre>

  1258         <li>Otherwise,

  1259             calculate its outer size as in the previous case,

  1260             but set each box's <i>flex factor</i> as proportional to

  1261             its outer <i>min-content width</i>.

  1262       </ol>

  1263       In each case, both <i>flex factors</i> are assumed to be ''1'' if their sum is equal to zero.

  1264     </li>

  1265   </ul>

  1267   <p>If the middle box (B) is <i>generated</i>,

  1268   determine the ''auto'' widths of A, B, and C as follows:

  1270   <ol>

  1271     <li>

  1272       First, resolve any ''auto'' width of the middle box (B):

  1273       Assume there are two boxes, B and AC,

  1274       where each of AC's dimensions is double the maximum of A and C.

  1275       (This preserves B's centering.)

  1276       Distribute the space to these two boxes (B and the imaginary AC)

  1277       as described for A and C <a href="#fit2">above</a>.

  1278     <li>

  1279       Then, resolve any ''auto'' widths of the side boxes (A and C)

  1280       by setting that box's outer width to

  1281       <pre>(<i>available width</i> &minus; <i>used outer size of B</i>) ÷ 2<pre>

  1282     </li>

  1283   </ol>

  1285 <h5 id="variable-minmax">Handling 'min-width' and 'max-width'</h5>

  1287 <p>

  1288   The 'min-width' and 'max-width' properties [[CSS21]] apply to page-margin

  1289   boxes in the variable dimension like on normal elements, except that the

  1290   three boxes on the same side are considered together.

  1291 </p>

  1293 <p>

  1294   More precisely:

  1295 </p>

  1297 <ol>

  1298   <li>

  1299     The tentative used widths are calculated

  1300     (without 'min-width' and 'max-width') following the rules under

  1301     <a href="#marginbox-variabledim-with">Resolving ''auto'' widths</a>

  1302     above.

  1303   </li>

  1304   <li>

  1305     If the tentative used width of any of the three boxes

  1306     is greater than 'max-width', the rules above are applied again,

  1307     but this time using the computed value of 'max-width'

  1308     as the computed value for 'width'.

  1309   </li>

  1310   <li>

  1311     If the resulting width of any of the three boxes

  1312     is smaller than 'min-width', the rules above are applied again,

  1313     but this time using the value of 'min-width'

  1314     as the computed value for 'width'.

  1315   </li>

  1316 </ol>

  1318 <h5 id="variable-position">Positioning</h5>

  1320 <p>

  1321   Once the dimensions of the boxes are determined,

  1322   they are positioned as follows:

  1323 </p>

  1325 <ul>

  1326   <li>The left outer edge of A is flush with the left edge of the

  1327       containing block</li>

  1328   <li>The outer area of B is centered in the containing block.</li>

  1329   <li>The right outer edge of C is flush with the right edge of the

  1330       containing block.</li>

  1331 </ul>

  1333 <h5 id="variable-mapping">Boxes on other sides</h5>

  1335 <p>The used values for 'bottom-left', 'bottom-center' and 'bottom-right'

  1336 page-margin boxes are established by the same rules as

  1337 for 'top-left', 'top-center', and 'top-right', respectively.</p>

  1339 <p>The used values for 'left-top', 'left-middle' and 'left-bottom' boxes are

  1340 established by the same rules, with "width" replaced by "height", "left" by

  1341 "top", "right" by "bottom" and "center" by "middle".</p>

  1343 <p>The used values for 'right-top', 'right-middle' and 'right-bottom'

  1344 page-margin boxes

  1345 are established by the same rules as for 'left-top', 'left-middle' and

  1346 'left-bottom', respectively.</p>

  1348 <h4 id="fixed-sizing">Page-Margin Box Fixed Dimension Computation Rules</h4>

  1350 <p>The rules below are used to calculate the used values of each

  1351 'top-left-corner', 'top-left', 'top-center', 'top-right', and

  1352 'top-right-corner' page-margin box's 'height', 'margin-top', and 'margin-bottom'

  1353 properties:</p>

  1355 <ol>

  1356   <li>The following constraint must hold among the used values of the margin

  1357   box's properties:

  1358   <p>'margin-top' + 'border-top-width' + 'padding-top' + 'height' +

  1359   'padding-bottom' + 'border-bottom-width' + 'margin-bottom' = top page margin

  1361   <li>If 'border-top-width' + 'padding-top' + 'height' (if it is not ''auto'')

  1362   + 'padding-bottom' + 'border-bottom-width', plus 'margin-top' and/or

  1363   'margin-bottom' if not ''auto'', is larger than the height of the top page

  1364   margin, then any ''auto'' values for 'margin-top' or 'margin-bottom' are, for

  1365   the following rules, treated as zero.

  1367   <li>If at this point all of 'height', 'margin-top', and 'margin-bottom'

  1368   have a computed value other than ''auto'', the values are said to be

  1369   "over-constrained". In this case, the specified value of 'margin-top' is

  1370   treated as 'auto'.

  1372   <li>If there is now exactly one value specified as 'auto', its used value

  1373   follows from the equality.

  1375   <li>If 'height' is set to 'auto', any other 'auto' values become '0' and

  1376   'height' follows from the resulting equality

  1378   <li>If both 'margin-top' and 'margin-bottom' are 'auto',

  1379   their used values are equal.

  1380   This vertically centers the page-margin box content

  1381   within the top page margin.

  1382 </ol>

  1384 <p>The same rules apply to the bottom page-margin boxes (bottom-left-corner,

  1385 bottom-left, bottom-center, bottom-right, and bottom-right-corner), except that

  1386 in the overconstrained case, the 'margin-bottom' is ignored rather than the

  1387 'margin-top'.</p>

  1389 <p>Analogous rules govern the properties for the left and right

  1390 page-margin boxes with respect to 'width'

  1391 (top-left-corner, left-top, left-middle, left-bottom, and

  1392 bottom-left-corner; top-right-corner, right-top, right-middle, right-bottom,

  1393 bottom-right-corner), with 'top' replaced by 'left', 'bottom' replaced by

  1394 'right', and 'height' replaced by 'width'.

  1395 In the overconstrained case for left (right) page-margin boxes,

  1396 the specified value of 'margin-left' ('margin-right') is ignored.</p>

  1398 <h3 id="margin-box-ex">Page-margin box examples</h3>

  1400 <p>The following is a collection of examples of page-margin box usage.</p>

  1402 <div class="example">

  1404 <p>Here is an example of a page with only a top-left header:</p>

  1405 <pre>

  1406 @page {

  1407 @top-left { content: "Header in Left Cell (top-left)" }

  1408 }

  1409 </pre>

  1411 <p>Because there are no contents defined for the top-center or the top-right

  1412 page-margin boxes, the extent of the top-left page-margin box

  1413 is allowed to cross the center of the page box.</p>

  1415 <p><img alt="Header Example 1" src="header-ex-1.png" height="177" width="737"></p>

  1416 </div>

  1418 <div class="example">

  1420 <p>The following is an example of a page with a centered header:</p>

  1421 <pre>

  1422 @page {

  1423 @top-center { content: "Header in Center Cell (top-center)" }

  1424 }

  1425 </pre>

  1427 <p><img alt="Header Example 2" src="header-ex-2.png" height="177" width="737"></p>

  1428 </div>

  1430 <div class="example">

  1432 <p>The following is an example of a page with a single header in the top-right

  1433 page-margin box:</p>

  1434 <pre>

  1435 @page {

  1436 @top-right { content: "Header in Right Cell (top-right)" }

  1437 }

  1438 </pre>

  1440 <p>Because the content of the center cell is empty, the extent of the top-right

  1441 page-margin box is allowed to cross the center of the page box.</p>

  1443 <p><img alt="Header Example 3" src="header-ex-3.png" height="177" width="737"></p>

  1444 </div>

  1446 <div class="example">

  1448 <p>The following is an example of a page with a top-center and a top-left header:</p>

  1449 <pre>

  1450 @page {

  1451 @top-left { content: "Left Cell (top-left)" }

  1452 @top-center { content: "Header in Center Cell (top-center)" }

  1453 }

  1454 </pre>

  1456 <p><img alt="Header Example 4" src="header-ex-4.png" height="177" width="737"></p>

  1457 </div>

  1459 <div class="example">

  1461 <p>The following is an example of a page with a top-center and a top-right header:</p>

  1462 <pre>

  1463 @page {

  1464 @top-center { content: "Header in Center Cell (top-center)" }

  1465 @top-right { content: "Right Cell (top-right)" }

  1466 }

  1467 </pre>

  1469 <p><img alt="Header Example 5" src="header-ex-5.png" height="177" width="737"></p>

  1470 </div>

  1472 <div class="example">

  1474 <p>The following is an example of a page with top-left and top-right headers:</p>

  1475 <pre>

  1476 @page {

  1477 @top-left { content: "Header in top-left with approx. "

  1478                    "twice as many words as right cell." }

  1479 @top-right { content: "Right cell (top-right)" }

  1480 }

  1481 </pre>

  1483 <p>Because there are no center cell contents, the extent of the top-left is

  1484 allowed to cross the center of the page box.</p>

  1486 <p><img alt="Header Example 6" src="header-ex-6.png" height="177" width="737"></p>

  1487 </div>

  1489 <h2 id="page-properties">Page Properties</h2>

  1490 <div>

  1492 <p>

  1493   <a href="#properties-list">Appendix A</a> defines the normative list of

  1494   CSS 2.1 [[!CSS21]]

  1495   <a href="#page-property-list">properties that apply to page boxes</a>.

  1496   If a conforming user agent supports any of these properties on block boxes,

  1497   then it <em class="RFC2119">MUST</em> also support that property

  1498   in the <i>page context</i>.

  1499   This specification additionally defines the 'size' property

  1500   that only applies in the page context.

  1502 <p>

  1503   Properties that apply to the page-margin boxes can also be set

  1504   within the page context:

  1505   if inheritable or explicitly inherited

  1506   (with the ''inherit'' keyword in the margin context),

  1507   they will inherit to the page-margin boxes.

  1509 <p>

  1510   The same appendix defines the normative list of

  1511   CSS 2.1 [[!CSS21]]

  1512   <a href="#page-property-list">properties that apply to page-margin boxes</a>.

  1513   If a conforming user agent supports any of these properties on block boxes,

  1514   then it <em class="RFC2119">MUST</em> also support that property

  1515   in the <i>margin context</i>

  1516   (except for <code>z-index</code>, which is optional for page-margin boxes.)

  1518 <p>

  1519   Other properties defined by [[!CSS21]] do not apply in these contexts.

  1520   Behavior for properties not included in CSS 2.1 is undefined.

  1522 <p class="note">

  1523 Note: The intent of leaving other properties undefined is to allow the gradual

  1524 addition of appropriate CSS3 properties as they emerge, without having to

  1525 update this specification with each addition.</p>

  1527 <p><a href="http://www.w3.org/TR/CSS21/cascade.html#value-stages">As with

  1528 elements in the document</a>, both the page context and the margin context

  1529 have a computed value for every property, even if that property does not

  1530 apply to the page or page-margin box.</p>

  1532 <p>The normal rules for CSS properties apply with the following exceptions:</p>

  1534 <ul>

  1535   <li>page-margin boxes inherit from the page context.

  1536   The page context inherits from the root element.

  1537   However, since the previous revision of CSS Paged

  1538   Media Level 3 did not specify this point, an implementation that sets

  1539   inherited properties in the page context to their initial values (as for the

  1540   root element) is also conformant to CSS Paged Media Level 3. Note that this

  1541   exception will be removed in Level 4.

  1542   <li>Values in units of ''em'' and ''ex'' are interpreted relative to the font

  1543   associated with their context. When used on the 'font-size' property in the

  1544   margin context, they are relative to the font of the page context. When used

  1545   on the 'font-size' property in the page context, they are relative to the

  1546   'font-size' of the root element. However, since a previous revision of CSS

  1547   Paged Media Level 3 was ambiguous on this point, an implementation that

  1548   treats ''em'' and ''ex'' on 'font-size' as relative to the initial value is

  1549   also conformant to CSS Paged Media Level 3. Note that this exception will

  1550   be removed in Level 4.

  1551   <li>Percentage values on the margin and padding properties are relative to the

  1552   dimensions of the containing block. For right and left values, percentages are

  1553   relative to the width of the containing block; for top and bottom values,

  1554   percentages are relative to the height of the containing block.</li>

  1555   <li>The used values of 'width' and 'height' have special computation rules

  1556   for page boxes and page-margin boxes; see <a href="#page-size">Page Size</a>

  1557   and <a href="#margin-box-dimensions">Computing Page-Margin Box Dimensions</a>.

  1558   <li>The page background is positioned and painted

  1559     <a href="#painting">as described above</a>.

  1560   <li>The rules for counter scoping are modified <a href="page-based-counters">as

  1561   described below</a>.</li>

  1562   <li>

  1563     As on the '::before' and '::after' pseudo-elements,

  1564     the ''normal'' value of the 'content' property computes to ''none''

  1565     on page-margin boxes.

  1566   </li>

  1567   <li>On page-margin boxes, the 'vertical-align' property behaves

  1568   <a href="http://www.w3.org/TR/CSS21/tables.html#height-layout">as specified for table cells</a>.

  1569   It <em>always</em> performs alignment in the vertical dimension,

  1570   regardless of writing mode.

  1571 </ul>

  1573 <p>It is <em class="RFC2119">recommended</em> that user agents establish a default

  1574 page margin via the user agent stylesheet that includes any non-printable area.

  1575 It is further <em class="RFC2119">recommended</em> that authors assume that the

  1576 default page area will not include unprintable regions.</p>

  1578 <h3 id="page-based-counters">Page-based counters</h3>

  1580 <p>Counters can be defined and controlled within an <span class="css">'@page'</span>

  1581 rule, and used as content in page-margin boxes.

  1582 This is useful for maintaining a page count.</p>

  1584 <p>A 'counter-increment' within either a page or margin context causes the counter

  1585 to increment with the generation of each page box.</p>

  1587 <p>If a counter is reset or incremented within the page context, it is in scope

  1588 for all page-margin boxes and obscures all counters of the same name within the

  1589 document.</p>

  1591 <p>If a counter is reset or incremented within a margin context, it is in scope

  1592 for that page-margin box and obscures any counters of the same name

  1593 in both the page context and the document.</p>

  1595 <p>If a counter that has not been reset or incremented within the margin context

  1596 or the page context is used by counter() or counters() in the margin context,

  1597 then the resultant value is exactly

  1598 as if the page-margin box were an element within

  1599 the document at the start of the page, inside the deepest element in the normal

  1600 flow that spans the page break. Use of the counter in this way does not affect

  1601 the calculation of the counter's value.</p>

  1603 <p>

  1604   A counter named ''page'' is automatically created

  1605   and incremented by 1 on every page of the document,

  1606   unless the 'counter-increment' property in the <i>page context</i>

  1607   explicitly specifies a different increment for the ''page'' counter.

  1608   The implied ''page'' counter is a real counter,

  1609   and can be directly affected using the 'counter-increment' and 'counter-reset' properties

  1610   when named explicitly in those properties.

  1611   It can also be used in the 'counter()' and 'counters()' function forms.

  1612 </p>

  1614 <div class="example">

  1615 <p>The following rules result in the placement of the current page number in the

  1616 middle of the outside margin of each page.</p>

  1617 <pre>

  1618 @page {

  1619   margin: 10%;

  1621   @top-center {

  1622     font-family: sans-serif;

  1623     font-weight: bold;

  1624     font-size: 2em;

  1625     content: counter(page);

  1626   }

  1627 }

  1628 </pre>

  1630 <p>Adding the following rule will make all pages even-numbered.</p>

  1631 <pre>

  1632 @page {

  1633   counter-increment: page 2;

  1634 }

  1635 </pre>

  1636 </div>

  1638 <p>Additionally, a counter named ''pages'' is automatically created by the UA.

  1639 Its value is always the total number of pages in the document. (In continuous

  1640 media this is always 1.) The value of ''pages'' cannot be manipulated: while

  1641 'counter-reset' and 'counter-increment' statements that set it are valid, they

  1642 have no effect.

  1644 <p>In all other respects, page-associated counters behave as described in

  1645 [[!CSS21]], <a href="TR/CSS21/generate.html#scope">Nested Counters and

  1646 Scope</a> and <a href="http://www.w3.org/TR/CSS21/syndata.html#counter">Counters</a>.</p>

  1648 <h3 id="margin-text-alignment">Page-margin boxes and default values</h3>

  1650 <p>Properties used within page or margin contexts take their initial values from

  1651 their respective property definitions; however, user agents must behave as

  1652 though the values in the following table were established by rules in the UA

  1653 default style sheet.</p>

  1654 <table id="margin-values" class="data" summary="definition of page-margin box default properties">

  1655   <caption>Table 2. Default values for Page-Margin Boxes</caption>

  1656   <thead>

  1657     <tr>

  1658       <th>Page-margin box</th>

  1659       <th><span class="property">'text-align'</span></th>

  1660       <th><span class="property">'vertical-align'</span></th>

  1661     </tr>

  1662   </thead>

  1663   <tbody>

  1664     <tr>

  1665       <td><a href="#top-left-corner-box-def">top-left-corner</a></td>

  1666       <td>right</td>

  1667       <td>middle</td>

  1668       </tr>

  1669     <tr>

  1670       <td><a href="#top-left-box-def">top-left</a></td>

  1671       <td>left</td>

  1672       <td>middle</td>

  1673       </tr>

  1674     <tr>

  1675       <td><a href="#top-center-box-def">top-center</a></td>

  1676       <td>center</td>

  1677       <td>middle</td>

  1678       </tr>

  1679     <tr>

  1680       <td><a href="#top-right-box-def">top-right</a></td>

  1681       <td>right</td>

  1682       <td>middle</td>

  1683       </tr>

  1684     <tr>

  1685       <td><a href="#top-right-corner-box-def">top-right-corner</a></td>

  1686       <td>left</td>

  1687       <td>middle</td>

  1688       </tr>

  1689     <tr>

  1690       <td><a href="#left-top-box-def">left-top</a></td>

  1691       <td>center</td>

  1692       <td>top</td>

  1693       </tr>

  1694     <tr>

  1695       <td><a href="#left-middle-box-def">left-middle</a></td>

  1696       <td>center</td>

  1697       <td>middle</td>

  1698       </tr>

  1699     <tr>

  1700       <td><a href="#left-bottom-box-def">left-bottom</a></td>

  1701       <td>center</td>

  1702       <td>bottom</td>

  1703       </tr>

  1704     <tr>

  1705       <td><a href="#right-top-box-def">right-top</a></td>

  1706       <td>center</td>

  1707       <td>top</td>

  1708       </tr>

  1709     <tr>

  1710       <td><a href="#right-middle-box-def">right-middle</a></td>

  1711       <td>center</td>

  1712       <td>middle</td>

  1713       </tr>

  1714     <tr>

  1715       <td><a href="#right-bottom-box-def">right-bottom</a></td>

  1716       <td>center</td>

  1717       <td>bottom</td>

  1718       </tr>

  1719     <tr>

  1720       <td><a href="#bottom-left-corner-box-def">bottom-left-corner</a></td>

  1721       <td>right</td>

  1722       <td>middle</td>

  1723       </tr>

  1724     <tr>

  1725       <td><a href="#bottom-left-box-def">bottom-left</a></td>

  1726       <td>left</td>

  1727       <td>middle</td>

  1728       </tr>

  1729     <tr>

  1730       <td><a href="#bottom-center-box-def">bottom-center</a></td>

  1731       <td>center</td>

  1732       <td>middle</td>

  1733       </tr>

  1734     <tr>

  1735       <td><a href="#bottom-right-box-def">bottom-right</a></td>

  1736       <td>right</td>

  1737       <td>middle</td>

  1738       </tr>

  1739     <tr>

  1740       <td><a href="#bottom-right-corner-box-def">bottom-right-corner</a></td>

  1741       <td>left</td>

  1742       <td>middle</td>

  1743     </tr>

  1744   </tbody>

  1745 </table>

  1747 <div class="example">

  1749 <p>This example style sheet could be used to create a centered header with the

  1750 current chapter name:</p>

  1751 <pre>body {counter-reset: chapter;}

  1752 div.chapter {counter-increment: chapter;}

  1753 @page {

  1754 margin: 10%;

  1755 @top-center { content: "Chapter" counter(chapter) }

  1756 }

  1757 </pre>

  1758 </div>

  1760 <h2 id="page-size">Page Size</h2>

  1762 <p>People around the world use many different paper sizes. It is a goal of this

  1763 specification that web content should be adaptable to a range of different

  1764 sizes without having to write a specific style sheet for each paper size.</p>

  1766 <p>However, in some situations it is important that a certain page size achieves a

  1767 certain style. One way to achieve this goal is to utilize the 'size' property,

  1768 which indicates that the document should preferentially be displayed on a

  1769 surface of a certain size; another method is to use Media Queries [[MEDIAQ]]

  1770 which allow different style sheets to be applied to different page sizes.</p>

  1772 <h3 id="page-size-prop">Page size: the 'size' property</h3>

  1774 <table class="propdef" summary="definition of the size property">

  1775   <tr>

  1776     <th>Name:

  1777     <td><dfn id="size">size</dfn>

  1778   <tr>

  1779     <th>Value:

  1780     <td>&lt;length&gt;{1,2} | auto | [ &lt;page-size&gt; || [ portrait | landscape] ]

  1781   <tr>

  1782     <th>Initial:

  1783     <td>auto

  1784   <tr>

  1785     <td><em>Applies to:</em>

  1786     <td>page context

  1787   <tr>

  1788     <th>Inherited:

  1789     <td>N/A

  1790   <tr>

  1791     <th>Percentages:

  1792     <td>N/A

  1793   <tr>

  1794     <th>Media:

  1795     <td>paged

  1796   <tr>

  1797     <td><em>Computed value:</em>

  1798     <td>specified value

  1799 </table>

  1801 <p>This property specifies the target size and orientation of the

  1802 <a href="#page-box">page box</a>’s containing block.

  1803 In the general case, where one page box is rendered onto one <a href="#page-sheet">page sheet</a>,

  1804 the 'size' property also indicates the size of the destination page sheet.

  1806 <p>The size of a page box can either be "absolute" (fixed size) or "scalable"

  1807 (i.e., fitting available sheet sizes).

  1808 The first three values in the table below can be used to create scalable page

  1809 boxes.

  1810 Other values define a fixed-size page box, and thereby indicate the preferred

  1811 output media size. When possible, output should be rendered on the media size

  1812 indicated.

  1813 If the specified size is not available, the rules for

  1814 <a href="#renderingpages">transposing a page box to a different size</a>

  1815 apply.</p>

  1817 <p>If a <code>size</code> property declaration is qualified by a ''width'',

  1818 ''height'', ''device-width'', ''device-height'', ''aspect-ratio'',

  1819 ''device-aspect-ratio'' or ''orientation''

  1820 media query [[!MEDIAQ]] (or other conditional on the size of the paper), then

  1821 the declaration must be

  1822 <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignored</a>. Media

  1823 queries do not honor 'size': they assume the paper size that would be chosen

  1824 if no @page rules were specified.</p>

  1826 <p class=issue>It would be useful if media queries could respond at least

  1827 to sizes specified on an unqualified @page.

  1829 <div class="example">

  1830   <p>In the following example

  1831   <pre>

  1832   @page {

  1833     size: 4in 6in;

  1834   }

  1836   @media (max-width: 6in) {

  1837     @page {

  1838       size: letter;

  1839     }

  1840   }

  1841   </pre>

  1842   <p>The second <code>size</code> declaration is ignored, i.e. the specified value

  1843   of the <code>size</code> property is <code>4in 6in</code>.

  1844 </div>

  1846 <table class="page-sizes">

  1847 <tr>

  1848 <th>Value</th>

  1849 <th>Description</th>

  1850 </tr>

  1851 <tr>

  1852 <td>auto</td>

  1853 <td>The page box will be set to a size and orientation chosen by the UA. In the

  1854 usual case, the page box size and orientation is chosen to match the target

  1855 media sheet.</td>

  1856 </tr>

  1857 <tr>

  1858 <td>landscape</td>

  1859 <td>Specifies that the page's content be printed in landscape orientation. The

  1860 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

  1861 is chosen by the UA.</td>

  1862 </tr>

  1863 <tr>

  1864 <td>portrait</td>

  1865 <td>Specifies that the page's content be printed in portrait orientation. The

  1866 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

  1867 is chosen by the UA.</td>

  1868 </tr>

  1869 <tr>

  1870 <td>&lt;length&gt;</td>

  1871 <td>The page box will be set to the given absolute dimension(s). If only one length

  1872 value is specified, it sets both the width and height of the page box (i.e.,

  1873 the box is a square). If two length values are specified, the first establishes

  1874 the page box width, and the second the page box height. Values in units of

  1875 <span class="css">'em'</span> and <span class="css">'ex'</span> refer to the

  1876 page context's font. Negative lengths are illegal.</td>

  1877 </tr>

  1878 <tr>

  1879 <td>&lt;page-size&gt;</td>

  1880 <td>A page size can be specified using one of the following media names. This is

  1881 the equivalent of specifying the <span class="css">'&lt;page-size&gt;'</span>

  1882 using length values. The definition of the the media names comes from

  1883 <cite>Media Standardized Names</cite> [[!PWGMSN]].

  1885 <dl>

  1887 <dt>A5</dt>

  1888 <dd>Equivalent to the size of ISO A5 media: 148mm wide and 210 mm high.</dd>

  1890 <dt>A4</dt>

  1891 <dd>Equivalent to the size of ISO A4 media: 210 mm wide and 297 mm high.</dd>

  1893 <dt>A3</dt>

  1894 <dd>Equivalent to the size of ISO A3 media: 297mm wide and 420mm high.</dd>

  1896 <dt>B5</dt>

  1897 <dd>Equivalent to the size of ISO B5 media: 176mm wide by 250mm high.</dd>

  1899 <dt>B4</dt>

  1900 <dd>Equivalent to the size of ISO B4 media: 250mm wide by 353mm high.</dd>

  1902 <dt>letter</dt>

  1903 <dd>Equivalent to the size of North American letter media: 8.5 inches wide and 11

  1904 inches high</dd>

  1906 <dt>legal</dt>

  1907 <dd>Equivalent to the size of North American legal: 8.5 inches wide by 14 inches

  1908 high.</dd>

  1910 <dt>ledger</dt>

  1911 <dd>Equivalent to the size of North American ledger: 11 inches wide by 17 inches

  1912 high.</dd>

  1913 </dl></td>

  1914 </tr>

  1915 </table>

  1917 <p>The '&lt;page-size&gt;' names can be used in conjunction with 'landscape' or

  1918 'portrait' to indicate both size and orientation.</p>

  1920 <h4>Some examples:</h4>

  1922 <div class="example">

  1923 <pre>

  1924 @page {

  1925 size: A4 landscape;

  1926 }

  1927 </pre>

  1929 <p>The above example sets the width of the page box to be 297mm and the height to

  1930 be 210mm. The page box in this example should be rendered on a page sheet size

  1931 of 210 mm by 297 mm.</p>

  1932 </div>

  1934 <div class="example">

  1936 <p>In the following example, the outer edges of the page box will align with the

  1937 page. The percentage value on the <span class="property">'margin'</span>

  1938 property is relative to the page size so if the page sheet dimensions are 210mm

  1939 x 297mm (i.e., A4), the margins are 21mm and 29.7mm. Assuming there are no page

  1940 borders or padding set in the UA default style sheet, the resulting page area

  1941 is 189mm by 367.3mm (210mm-21mm by 297mm-29.7mm).</p>

  1942 <pre>

  1943 @page {

  1944 size: auto;/* auto is the initial value */

  1945 margin: 10%;

  1946 }

  1947 </pre>

  1948 </div>

  1950 <div class="example">

  1951 <pre>

  1952 @page {

  1953 size: 8.5in 11in;/* width height */

  1954 }

  1955 </pre>

  1957 <p>The above example sets the width of the page box to be 8.5 inches and the

  1958 height to be 11 inches. This indicates that the page sheet size should be

  1959 8.5"x11" and the orientation 'portrait'.</p>

  1960 </div>

  1962 <h4 id="page-size-media-query">Media Queries</h4>

  1964 <p>This section is informative.</p>

  1966 <p>By using Media Queries [[MEDIAQ]], one style sheet can express different

  1967 stylistic preferences for different page sizes. Consider this example:</p>

  1969 <div class="example" style="font-size: 10pt;">

  1970 <pre>

  1971  /* style sheet for "A4" printing */

  1972  @media print and (width: 21cm) and (height: 29.7cm) {

  1973     @page {

  1974        margin: 3cm;

  1975     }

  1976  }

  1978  /* style sheet for "letter" printing */

  1979  @media print and (width: 8.5in) and (height: 11in) {

  1980     @page {

  1981         margin: 1in;

  1982     }

  1983  }

  1984 </pre>

  1985 </div>

  1987 <p>In the example above, "A4" sheets are given a "3cm" page margin, and "letter"

  1988 sheets are given a "1in" page margin.</p>

  1990 <h3 id="renderingpages">Rendering page boxes that do not fit a page sheet</h3>

  1992 <p>If a page box does not match the target page sheet dimensions, the user agent

  1993 should do one of the following (in order of preference):</p>

  1995 <ol>

  1996   <li>Render the page box at the indicated size on a larger page sheet.</li>

  1997   <li>Rotate the page box 90° if this will make the page box fit the page sheet.</li>

  1998   <li>Scale the page box to fit the page sheet. (The aspect ratio of the page box

  1999   <em class="RFC2119">should</em> be preserved.)</li>

  2000   <li>Graphically "slice" the page box onto multiple page sheets.</li>

  2001   <li>Clip overflowed content (least preferred).</li>

  2002 </ol>

  2004 <p>The user agent <em class="RFC2119">MAY</em> wish to consult the user before

  2005 performing these operations.</p>

  2007 <h3 id="positioning-page-box">Positioning the page box on the sheet</h3>

  2009 <p>When the page box is smaller than the page sheet, the user agent <em class="RFC2119">SHOULD</em> either:</p>

  2011 <ul>

  2012   <li>center the page box on the sheet since this will align double-sided pages

  2013   and avoid accidental loss of information that is printed near the edge of the

  2014   sheet; or</li>

  2015   <li>position the page box in the upper left corner of the page sheet

  2016   (or another corner,

  2017   based on the 'direction' and 'writing-mode' properties of the page box)

  2018   as this may minimize media consumption.</li>

  2019 </ul>

  2021 <p>The user agent <em class="RFC2119">MAY</em> wish to consult the user in this

  2022 regard.</p><!-- "Page selector and page context" -->

  2024 <h2 id="page-breaks">

  2025     <a id="pg-br-before-after"></a>

  2026     <a id="page-break-before"></a>

  2027     <a id="page-break-after"></a>

  2028     <a id="page-break-inside"></a>

  2029     <a id="breaks-inside"></a>

  2030     <a id="orphans"></a>

  2031     <a id="widows"></a>

  2032     <a id="allowed-pg-brk"></a>

  2033     <a id="brk-btw-blocks"></a>

  2034     <a id="brk-btw-lines"></a>

  2035     <a id="brk-end-block"></a>

  2036     <a id="forced-pg-brk"></a>

  2037     <a id="best-pg-brk"></a>

  2038     Page Breaks

  2039 </h2>

  2041 <p>

  2042   The CSS Fragmentation Module [[!CSS3-BREAK]] module

  2043   defines how and where CSS boxes

  2044   can be <i>fragmented</i>, including across page breaks.

  2045   It defines a few properties that indicate where the user agent

  2046   <em class="RFC2119">MAY</em> or <em class="RFC2119">MUST</em> break pages,

  2047   and on what page (left or right) the subsequent content resumes.

  2048   Each page break ends layout in the current <a href="#page-box">page box</a>

  2049   and causes remaining pieces of the document tree to be laid out

  2050   in a new page box.

  2051 </p>

  2053 <h3 id="using-named-pages">Using named pages: 'page'</h3>

  2054 <table class="propdef" summary="property definition">

  2055   <tr>

  2056     <th>Name:

  2057     <td><dfn id="page">page</dfn>

  2058   <tr>

  2059     <th>Value:

  2060     <td>auto | &lt;identifier&gt;

  2061   <tr>

  2062     <th>Initial:

  2063     <td>auto

  2064   <tr>

  2065     <th>Applies to:

  2066     <td>boxes that create <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class 1</a> break points

  2067   <tr>

  2068     <th>Inherited:

  2069     <td>no (but see prose)

  2070   <tr>

  2071     <th>Percentages:

  2072     <td>N/A

  2073   <tr>

  2074     <th>Media:

  2075     <td>paged

  2076   <tr>

  2077     <th>Computed value:

  2078     <td>specified value

  2079 </table>

  2081 <p>

  2082   The 'page' property is used to specify a particular type of page (called a <dfn>named page</dfn>)

  2083   on which an element <em class="RFC2119">MUST</em> be displayed.

  2084   If necessary, a <i>forced page break</i> is introduced

  2085   and a new page generated of the specified type.

  2087 <p class="note">

  2088   This page can be styled by using the same type name

  2089   in a <a href="#page-selectors">page selector</a>.

  2091 <p>

  2092   Page type names are case-sensitive identifiers.

  2093   However the ''auto'' value, being a CSS keyword, is

  2094   <a href="http://www.w3.org/TR/CSS21/syndata.html#characters">ASCII case-insensitive</a>.

  2096 <p>

  2097   The 'page' property does not inherit.

  2098   However, if the 'page' value on an element is ''auto'',

  2099   then its used value is the value specified

  2100   on its nearest ancestor with a non-auto value.

  2101   When specified on the root element,

  2102   the used value for ''auto'' is the empty string.

  2104   <!-- See http://www.w3.org/TR/2007/WD-css3-gcpm-20070504/#named3 -->

  2106 <p>

  2107   Because a previous version of this specification

  2108   indicated that the 'page' property is inherited,

  2109   an implementation that inherits the 'page' property

  2110   and treats ''auto'' as always naming the empty string

  2111   remains conformant to CSS Paged Media Level 3.

  2112   Note that this exception will be removed in Level 4.

  2113   Therefore authors should not explicitly specify the ''auto'' value

  2114   on a descendant of an element with a non-''auto'' value,

  2115   as the resulting behavior will be unpredictable.

  2117 <p>

  2118   The 'page' property works as follows:

  2120 <ol>

  2122   <li>

  2123     First, any ''auto'' values are resolved against non-''auto'' ancestors

  2124     (as specified above).

  2126   <li>

  2127     Next,

  2128     a <dfn>start 'page' value</dfn> and <dfn>end 'page' value</dfn>

  2129     is determined for each box

  2130     as the value (if any) propagated from its first or last child (respectively),

  2131     else the used value on the box itself.

  2132     A child propagates its own <i title="start page value">start</i> or <i>end 'page' value</i>

  2133     if and only if the 'page' property applies to it.

  2135   <li>

  2136     The first printed page’s type is the <i>start 'page' value</i> of the root.

  2138   <li>

  2139     If for any two boxes meeting at a <a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class 1</a> break point,

  2140     the <i>end 'page' value</i> of the box preceding the break

  2141     and <i>start 'page' value</i> of the box succeeding the break

  2142     do not match,

  2143     then a page break is forced between the two boxes,

  2144     and content after the break resumes on a page box of the named type.

  2145 </ol>

  2147 <p class="note">

  2148   Essentially, the two 'page' values compared are those from the deepest boxes

  2149   meeting at the class 1 break point,

  2150   ignoring any subtrees rooted by boxes to which the 'page' property does not apply.

  2152 <p>See [[!CSS3-BREAK]] for additional details on page breaks.

  2154 <div class="example">

  2156 <p>In this example, the two tables are rendered on landscape pages (indeed, on the

  2157 same page, if they fit). The page type "narrow" is used for the &lt;p&gt; after

  2158 the second table, as the page properties for the table element are no longer in

  2159 effect:</p>

  2160 <pre>

  2161 @page narrow { size: 9cm 18cm }

  2162 @page rotated { size: landscape }

  2163 div { page: narrow }

  2164 table { page: rotated }

  2165 </pre>with this document:

  2166 <pre>

  2167 &lt;div&gt;

  2168 &lt;table&gt;...&lt;/table&gt;

  2169 &lt;table&gt;...&lt;/table&gt;

  2170 &lt;p&gt;This text is rendered on a 'narrow' page&lt;/p&gt;

  2171 &lt;/div&gt;

  2172 </pre>

  2173 </div>

  2175 <div class="example">

  2176   <p>In Japanese documents, sometimes different parts of a single document

  2177   will have different <i lang="ja-Latn">kihon hanmen</i>. [[JLREQ]]

  2178   The 'page' property, together with ''@page'' rules specifying different page widths,

  2179   can accomodate this type of layout:

  2180   <pre>

  2181 &lt;!DOCTYPE html>

  2182 &lt;html lang="ja">

  2183   &lt;style>

  2184     html   { writing-mode: vertical-rl;

  2185              line-height: 1.6; }

  2186     .main  { page: main;

  2187              columns: 2; column-gap: 1rem; }

  2188     .index { page: index;

  2189              columns: 3; column-gap: 1rem; }

  2190     @page       { margin: auto;    /* center kihon hanmen on page */

  2191                   width:  40rem; } /* 1.6 &times; 25 lines        */

  2192     @page main  { height: 61rem; } /* 2 &times; 30 chars + 1 &times; gap */

  2193     @page index { height: 62rem; } /* 3 &times; 20 chars + 2 &times; gap */

  2194   &lt;/style>

  2195   &lt;section class="main"> ... &lt;/section>

  2196   &lt;section class="index"> ... &lt;/section>

  2197 &lt;/html>

  2198 </pre>

  2199 </div>

  2202 <h2 id="image-properties">Image Properties</h2>

  2204 <p class="note">This section has been moved to [[CSS3-IMAGES]].</p>

  2206 <h2 class="no-num" id="properties-list">Appendix A: Applicable CSS2.1 Properties</h2>

  2208 <h3 class="no-num" id="page-property-list">

  2209   CSS 2.1 Properties that apply within the page context</h3>

  2211 <p>

  2212   This list is described in the

  2213   <a href="#page-properties">Page Properties</a> section.

  2215 <table class="property-list">

  2216   <tbody>

  2217     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#direction">bidi properties</a>

  2218         <td>direction

  2219   <tbody>

  2220     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a>

  2221         <td>background-color

  2222     <tr><td>background-image

  2223     <tr><td>background-repeat

  2224     <tr><td>background-attachment

  2225     <tr><td>background-position

  2226     <tr><td>background

  2227   <tbody>

  2228     <tr><td rowspan="20"><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a>

  2229         <td>border-top-width

  2230     <tr><td>border-right-width

  2231     <tr><td>border-bottom-width

  2232     <tr><td>border-left-width

  2233     <tr><td>border-width

  2234     <tr><td>border-top-color

  2235     <tr><td>border-right-color

  2236     <tr><td>border-bottom-color

  2237     <tr><td>border-left-color

  2238     <tr><td>border-color

  2239     <tr><td>border-top-style

  2240     <tr><td>border-right-style

  2241     <tr><td>border-bottom-style

  2242     <tr><td>border-left-style

  2243     <tr><td>border-short-style

  2244     <tr><td>border-top

  2245     <tr><td>border-right

  2246     <tr><td>border-bottom

  2247     <tr><td>border-left

  2248     <tr><td>border

  2249   <tbody>

  2250     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a>

  2251         <td>counter-reset

  2252     <tr><td>counter-increment

  2253   <tbody>

  2254     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a>

  2255   <tbody>

  2256     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a>

  2257         <td>font-family

  2258     <tr><td>font-size

  2259     <tr><td>font-style

  2260     <tr><td>font-variant

  2261     <tr><td>font-weight

  2262     <tr><td>font

  2263   <tbody>

  2264     <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>

  2265         <td>height

  2266     <tr><td>min-height

  2267     <tr><td>max-height

  2268   <tbody>

  2269     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a>

  2270   <tbody>

  2271     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a>

  2272         <td>margin-top

  2273     <tr><td>margin-right

  2274     <tr><td>margin-bottom

  2275     <tr><td>margin-left

  2276     <tr><td>margin

  2277   <tbody>

  2278     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  2279         <td>outline-width

  2280     <tr><td>outline-style

  2281     <tr><td>outline-color

  2282     <tr><td>outline

  2283   <tbody>

  2284     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a>

  2285         <td>padding-top

  2286     <tr><td>padding-right

  2287     <tr><td>padding-bottom

  2288     <tr><td>padding-left

  2289     <tr><td>padding

  2290   <tbody>

  2291     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  2292   <tbody>

  2293     <tr><td rowspan="7"><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a>

  2294         <td>letter-spacing

  2295     <tr><td>text-align

  2296     <tr><td>text-decoration

  2297     <tr><td>text-indent

  2298     <tr><td>text-transform

  2299     <tr><td>white-space

  2300     <tr><td>word-spacing

  2301   <tbody>

  2302     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a>

  2303   <tbody>

  2304     <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>

  2305         <td>width

  2306     <tr><td>min-width

  2307     <tr><td>max-width

  2308 </table>

  2311 <h3 class="no-num" id="margin-property-list">

  2312   CSS 2.1 properties that apply within the margin contexts</h3>

  2314 <p>

  2315   This list is described in the

  2316   <a href="#page-properties">Page Properties</a> section.

  2318 <table class="property-list">

  2319   <tbody>

  2320     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#direction">bidi properties</a>

  2321         <td>direction

  2322     <tr><td>unicode-bidi

  2323   <tbody>

  2324     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/colors.html#background-properties">background properties</a>

  2325         <td>background-color

  2326     <tr><td>background-image

  2327     <tr><td>background-repeat

  2328     <tr><td>background-attachment

  2329     <tr><td>background-position

  2330     <tr><td>background

  2331   <tbody>

  2332     <tr><td rowspan="20"><a href="http://www.w3.org/TR/CSS21/box.html#border-properties">border properties</a>

  2333         <td>border-top-width

  2334     <tr><td>border-right-width

  2335     <tr><td>border-bottom-width

  2336     <tr><td>border-left-width

  2337     <tr><td>border-width

  2338     <tr><td>border-top-color

  2339     <tr><td>border-right-color

  2340     <tr><td>border-bottom-color

  2341     <tr><td>border-left-color

  2342     <tr><td>border-color

  2343     <tr><td>border-top-style

  2344     <tr><td>border-right-style

  2345     <tr><td>border-bottom-style

  2346     <tr><td>border-left-style

  2347     <tr><td>border-short-style

  2348     <tr><td>border-top

  2349     <tr><td>border-right

  2350     <tr><td>border-bottom

  2351     <tr><td>border-left

  2352     <tr><td>border

  2353   <tbody>

  2354     <tr><td rowspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#counters">counter properties</a>

  2355         <td>counter-reset

  2356     <tr><td>counter-increment

  2357   <tbody>

  2358     <tr><td colspan="2"><a href="">content</a>

  2359   <tbody>

  2360     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/colors.html#propdef-color">color</a>

  2361   <tbody>

  2362     <tr><td rowspan="6"><a href="http://www.w3.org/TR/CSS21/fonts.html">font properties</a>

  2363         <td>font-family

  2364     <tr><td>font-size

  2365     <tr><td>font-style

  2366     <tr><td>font-variant

  2367     <tr><td>font-weight

  2368     <tr><td>font

  2369   <tbody>

  2370     <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>

  2371         <td>height

  2372     <tr><td>min-height

  2373     <tr><td>max-height

  2374   <tbody>

  2375     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">line-height</a>

  2376   <tbody>

  2377     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#margin-properties">margin properties</a>

  2378         <td>margin-top

  2379     <tr><td>margin-right

  2380     <tr><td>margin-bottom

  2381     <tr><td>margin-left

  2382     <tr><td>margin

  2383   <tbody>

  2384     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/ui.html#dynamic-outlines">outline properties</a>

  2385         <td>outline-width

  2386     <tr><td>outline-style

  2387     <tr><td>outline-color

  2388     <tr><td>outline

  2389   <tbody>

  2390     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#overflow">overflow</a>

  2391   <tbody>

  2392     <tr><td rowspan="5"><a href="http://www.w3.org/TR/CSS21/box.html#padding-properties">padding properties</a>

  2393         <td>padding-top

  2394     <tr><td>padding-right

  2395     <tr><td>padding-bottom

  2396     <tr><td>padding-left

  2397     <tr><td>padding

  2398   <tbody>

  2399     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/generate.html#quotes-specify">quotes</a>

  2400   <tbody>

  2401     <tr><td rowspan="7"><a href="http://www.w3.org/TR/CSS21/text.html">text properties</a>

  2402         <td>letter-spacing

  2403     <tr><td>text-align

  2404     <tr><td>text-decoration

  2405     <tr><td>text-indent

  2406     <tr><td>text-transform

  2407     <tr><td>white-space

  2408     <tr><td>word-spacing

  2409   <tbody>

  2410     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">vertical-align</a>

  2411   <tbody>

  2412     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visufx.html#visibility">visibility</a>

  2413   <tbody>

  2414     <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>

  2415         <td>width

  2416     <tr><td>min-width

  2417     <tr><td>max-width

  2418   <tbody>

  2419     <tr><td colspan="2"><a href="http://www.w3.org/TR/CSS21/visuren.html#z-index">z-index</a>

  2420 </table>

  2422 <h2 class="no-num" id="transfer-possibilities">Appendix B: Transfer Possibilities</h2>

  2424 <p>Often, but not always, the page box has a one-to-one correspondence to the

  2425 physical surface onto which the document is ultimately rendered. The CSS3 page

  2426 model specifies formatting within the page box, but it is the user agent's

  2427 responsibility to transfer the page box to the sheet. Some user agent transfer

  2428 possibilities that are not addressed by CSS3 include:</p>

  2430 <ul id="complex-usecases">

  2431   <li>Transferring one page box to one sheet (e.g. single-sided printing);</li>

  2432   <li>Transferring two page boxes to the front and back surfaces of the same

  2433   sheet (e.g. double-sided printing);</li>

  2434   <li>Transferring N (small) page boxes to one sheet (called "N-up");</li>

  2435   <li>Transferring one (large) page box to N x M sheets (called "tiling");</li>

  2436   <li>Creating signatures. A <dfn>signature</dfn> is a group of pages printed on

  2437   a sheet, which, when folded and trimmed like a book, appear in their proper

  2438   sequence;</li>

  2439   <li>Printing one document to multiple output trays;</li>

  2440   <li>Generating files containing print instructions.</li>

  2441 </ul>

  2443 <h2 class="no-num" id="changes">Changes</h2>

  2445 <p>

  2446   Changes since the <a href="http://www.w3.org/TR/2006/WD-css3-page-20061010/">10 October 2006 Working Draft</a> are:

  2447 </p>

  2449 <ul>

  2450   <li>The first printed page can be <a href="#using-named-pages">named</a>.

  2452   <li>The '':blank'' <a href="#pseudo-classes">pseudo-class</a> was imported

  2453     from the <a href="http://dev.w3.org/csswg/css3-gcpm/">Generated Content for Paged Media</a> module.

  2455   <li>''@page'' rules can now take multiple comma separated selectors,

  2456     each selector can have multiple pseudo-classes.

  2458     <div class="example">

  2459       <pre>@page :first, :blank { @bottom-center { content: none } }</pre>

  2460       <pre>@page :first:left { @bottom-left { content: none } }</pre>

  2461     </div>

  2463   <li>Margin boxes are renamed <a href="#margin-boxes">page-margin boxes</a>,

  2464     to avoid confusion with the margin area of each box.

  2466   <li>The <a href="#variable-sizing">Variable Dimension</a>

  2467     layout rules for page-margin boxes have been much simplified

  2468     to not require quadratic optimization.

  2470   <li>The relative <a href="#painting">painting order</a>

  2471     of page-margin boxes and page content has changed.

  2473   <li>The description of page breaks and definition of related properties

  2474     (except for the 'page' property)

  2475     have been moved to the CSS Fragmentation Module. [[!CSS3-BREAK]]

  2477   <li>The 'fit' and 'fit-position' properties

  2478     are renamed to 'object-fit' and 'object-position',

  2479     redefined to enable additional use cases,

  2480     and moved to the CSS3 Image Values and Replaced Content module.

  2481     [[CSS3-IMAGES]]

  2483   <li>Many miscellaneous clarifications

  2484     and editorial improvements have been incorporated.

  2486 </ul>

  2489 <h2 class="no-num" id="references">References</h2>

  2491 <h3 class="no-num" id="normative-references">Normative References</h3><!--normative-->

  2493 <h3 class="no-num" id="informative-references">Informative References</h3><!--informative-->

  2494 </div>

  2495 </div>

  2496 </body>

  2497 </html>

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