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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang=en>
<head><meta content="text/html" http-equiv=Content-Type>
<title>CSS3 module: Cascading and inheritance</title>
<link href="../default.css" rel=stylesheet type="text/css">
<link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
type="text/css">
<style>
table { border-collapse: collapse; border: 1px solid black }
th, td { border: 1px solid black; padding: 0.2em; text-align: left }
.issue { color: red }
</style>
<body>
<div class=head> <!--begin-logo-->
<p><a href="http://www.w3.org/"><img alt=W3C height=48
src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
<h1>CSS3 module: Cascading and inheritance</h1>
<h2 class="no-num no-toc" id=longstatus>Editor's Draft 8 January 2009</h2>
<dl>
<dt>This version:
<dd><a
href="http://www.w3.org/TR/2009/ED-css3-cascade-20090108">http://www.w3.org/TR/2009/ED-css3-cascade-20090108</a>
<dt>Latest version:
<dd><a
href="http://www.w3.org/TR/css3-cascade">http://www.w3.org/TR/css3-cascade</a>
<dt>Previous version:
<dd><a
href="http://www.w3.org/TR/2005/WD-css3-cascade-20051215">http://www.w3.org/TR/2005/WD-css3-cascade-20051215</a>
<dt>Editor:
<dd>Håkon Wium Lie, Opera Software, howcome@opera.com
</dl>
<!--begin-copyright-->
<p class=copyright><a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
rel=license>Copyright</a> © 2009 <a
href="http://www.w3.org/"><acronym title="World Wide Web
Consortium">W3C</acronym></a><sup>®</sup> (<a
href="http://www.csail.mit.edu/"><acronym title="Massachusetts Institute
of Technology">MIT</acronym></a>, <a
href="http://www.ercim.org/"><acronym title="European Research Consortium
for Informatics and Mathematics">ERCIM</acronym></a>, <a
href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C <a
href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
<a
href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
and <a
href="http://www.w3.org/Consortium/Legal/copyright-documents">document
use</a> rules apply.</p>
<!--end-copyright-->
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc" id=abstract>Abstract</h2>
<p>This CSS3 module describes how to find the specified value for all
properties on all elements and boxes. Values either come from style sheets
or the property's initial value. By way of cascading and inheritance,
values are propagated to all properties on all elements and boxes.
<p>This module interfaces with several other modules. It relies on <a
href="#CSS3SYN" rel=biblioentry>[CSS3SYN]<!--{{!CSS3SYN}}--></a> to parse
the style sheets, on <a href="#SELECT"
rel=biblioentry>[SELECT]<!--{{!SELECT}}--></a> to calculate specificity,
and on <a href="#MEDIAQ" rel=biblioentry>[MEDIAQ]<!--{{!MEDIAQ}}--></a> to
determine if a declaration applies to the media. The output from this
module is a <em>specified value</em> for all element/property
combinations. The processing of specified values is described in <a
href="#CSS3VAL" rel=biblioentry>[CSS3VAL]<!--{{!CSS3VAL}}--></a>.
<h2 class="no-num no-toc" id=status>Status of this document</h2>
<p>This is a draft of a <a href="http://www.w3.org/TR/css3-roadmap/">module
of CSS level 3</a>. It will probably be bundled with some other modules
before it becomes a <a href="http://www.w3.org/TR/#About">W3C
Recommendation</a>.
<p>The main purpose of this module is to rewrite the relevant parts of CSS2
as a module for CSS3. With the exception of the ‘<code
class=css>initial</code>’ value and the optional title for
‘<code class=css>@import</code>’ and ‘<code class=css><a
href="#media">@media</a></code>’, all features described in this
module also exist in CSS2. Compared to CSS2, the cascading order has been
changed in two cases as noted in the text.
<p>This draft should not be cited except as "work in progress". It is a
work item of the CSS working group and part of the <a href="/Style/">Style
activity</a>. It may be modified or dropped altogether at any point in
time. Implementations for the purpose of experimenting with the
specification are welcomed, as long as they are clearly marked as
experimental.
<p>Feedback on this draft is invited. The preferred place for discussion is
the (<a
href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
mailing list <a href="http://www.w3.org/Mail/Lists.html#www-style"
lang=und>www-style@w3.org</a>. W3C members can also send comments to the
CSS WG mailing list.
<p>A list of current W3C Recommendations and other technical documents
including Working Drafts and Notes can be found at <a
href="http://www.w3.org/TR/">http://www.w3.org/TR</a>.
<h2 class="no-num no-toc" id=table>Table of contents</h2>
<!--begin-toc-->
<ul class=toc>
<li><a href="#introduction"><span class=secno>1. </span>Introduction</a>
<li><a href="#input"><span class=secno>2. </span>Input to and output from
this module</a>
<li><a href="#at-import"><span class=secno>3. </span>Importing style
sheets</a>
<li><a href="#at-media-rule"><span class=secno>4. </span>Named
<code>@media</code> rules</a>
<li><a href="#cascading"><span class=secno>5. </span>Cascading</a>
<li><a href="#inheritance"><span class=secno>6. </span>Inheritance</a>
<li><a href="#initial"><span class=secno>7. </span>Initial value</a>
<li><a href="#computing-weight"><span class=secno>8. </span>Computing
weight</a>
<li><a href="#conformance"><span class=secno>9. </span>Conformance</a>
<li class=no-num><a href="#acknowledgments">Acknowledgments</a>
<li class=no-num><a href="#references">References</a>
<ul class=toc>
<li class=no-num><a href="#normative-references">Normative
references</a>
<li class=no-num><a href="#other-references">Other references</a>
</ul>
<li class=no-num><a href="#index">Index</a>
<li class=no-num><a href="#property-index">Property index</a>
</ul>
<!--end-toc-->
<hr>
<h2 id=introduction><span class=secno>1. </span>Introduction</h2>
<p>One of the fundamental design principles of CSS is <em>cascading</em>,
which allows several style sheets to influence the presentation of a
document. When different declarations try to set a value for the same
element/property combination, the conflicts must somehow be resolved.
<p>The opposite problem arises when no declarations try to set a the value
for an element/property combination. In this case, a value must be found
by way of <em><a href="#inherited">inheritance</a></em> or by looking at
the <em><a href="#initial0">initial value</a></em>.
<p>The rules for finding a the specified value for all properties on all
elements and page/margin boxes is described in this specification.
<h2 id=input><span class=secno>2. </span>Input to and output from this
module</h2>
<p>The input to the computations described in this module is:
<ul>
<li>a set of parsed style sheets
<li>the initial value of each property
<li>the title of the preferred style sheet (if any)
</ul>
<p>The output of the computations described in this module is a specified
value for all properties on all elements and page/margin boxes.
<p>In order to find the specified values, implementations must first
identify which statements that apply to the document. This is done by:
<ol>
<li>Starting out with all author style sheets specified in the document,
as well all user and UA style sheets.
<li>Removing statements that have associated Media Queries <a
href="#MEDIAQ" rel=biblioentry>[MEDIAQ]<!--{{!MEDIAQ}}--></a> that are
false in the given context.
<li>Removing @import statements that do not match the title of the
preferred style sheet, if any. This is described in <a
href="#import">Importing style sheets</a> below.
<li>Removing @media statements that do not match the title of the
preferred style sheet, if any. This is described in <a
href="#import">Named @media rules</a> below.
<li>Expanding all remaining @import rules.
</ol>
<p>Then, for every element and every page/margin box, the value for each
property can be found by following this pseudo-algorithm:
<ol>
<li>Identify all declarations that apply to the element (as described in
<a href="#SELECT" rel=biblioentry>[SELECT]<!--{{!SELECT}}--></a>) or the
page/margin box (as described in <a href="#CSS3PAGE"
rel=biblioentry>[CSS3PAGE]<!--{{CSS3PAGE}}--></a>).
<li>If the cascading process (described below) yields a winning
declaration and the value of the winning declaration is not ‘<code
class=css>initial</code>’ or ‘<code
class=css>inherit</code>’, the value of the winning declaration
becomes the specified value.
<li>Otherwise, if the value of the winning declaration is ‘<code
class=css>inherit</code>’, the inherited value (see below) becomes
the specified value.
<li>Otherwise, if the value of the winning declaration is ‘<code
class=css>initial</code>’, the initial value (see below) becomes
the specified value.
<li>Otherwise, if the property is inherited, the inherited value becomes
the specified value.
<li>Otherwise, the initial value becomes the specified value.
</ol>
<p>The specified value may need some computation before it can be used.
This is described in the <a href="/TR/css3-values">Values and Units</a> <a
href="#CSS3VAL" rel=biblioentry>[CSS3VAL]<!--{{!CSS3VAL}}--></a> module.
<h2 id=at-import><span class=secno>3. </span>Importing style sheets</h2>
<p>The <dfn id=import>‘<code class=css>@import</code>’</dfn>
rule allows users to import style rules from other style sheets. Any
‘<code class=css>@import</code>’ rules must follow all
‘<code class=css>@charset</code>’ rules and precede all other
at-rules and rule sets in a style sheet. The ‘<code
class=css>@import</code>’ keyword must be followed by the URI of the
style sheet to include. A string is also allowed; it will be interpreted
as if it had url(…) around it.
<div class=example>
<p>The following lines are equivalent in meaning and illustrate both
‘<code class=css>@import</code>’ syntaxes (one with
‘<code class=css>url()</code>’ and one with a bare string):
<pre>
@import "mystyle.css";
@import url("mystyle.css");
</pre>
</div>
<p>So that user agents can avoid retrieving resources for unsupported media
types, authors may specify media-dependent @import rules. These <dfn
id=conditional title="conditional import|media-dependent
import">conditional imports</dfn> specify comma-separated “media
queries” after the URI.
<div class=example>
<p>The following rules illustrate how ‘<code
class=css>@import</code>’ rules can be made media-dependent:
<pre>
@import url("fineprint.css") print;
@import url("bluish.css") projection, tv;
@import url("narrow.css") handheld and (max-width: 400px);
</pre>
</div>
<p>The full syntax of the expressions after the URL is defined by the Media
Queries specification <a href="#MEDIAQ"
rel=biblioentry>[MEDIAQ]<!--{{!MEDIAQ}}--></a>.
<p>In the absence of any media queries, the import is unconditional.
Specifying ‘<code class=property>all</code>’ for the medium
has the same effect.
<p>At the end of the ‘<code class=css>@import</code>’ rule
(after any media queries), there may be a string that assigns a name to
the import.
<div class=example>
<pre>
@import url(layout1.css) screen "Plain style";
@import url(colors1.css) screen "Plain style";
@import url(style4.css) "Four-columns and dark";
</pre>
</div>
<p>Imports with different names (together with any named <a
href="#at-media-rule">@media rules,</a> see below) represent <dfn
id=alternative>alternative style sheets</dfn>. The UA should provide a way
for the user to select an alternative by name.
<p>The rules for which style sheet to import are as follows:
<ul>
<li>
<p>If the user has not chosen a style by name (e.g., he has indicated to
the UA that he wants the default style), then all ‘<code
class=css>@import</code>’s without a name are imported, as well as
the first ‘<code class=css>@import</code>’ that has a name
and all other ‘<code class=css>@import</code>’s that have
the same name.
<li>
<p>If the user has chosen a style be name, then all ‘<code
class=css>@import</code>’s without a name are imported, as well as
all ‘<code class=css>@import</code>’s with the name chosen
by the user.
</ul>
<div class=example>
<p>If the UA is using the default style, only “Yellow Fish”
and the nameless ‘<code class=css>@import</code>’s (shown in
<code><b>bold</b></code>) are used, the others are skipped:
<pre>
<b>@import "common1.css";</b>
<b>@import "yellowfish.css" "Yellow Fish";</b>
@import "simple.css" "Simple";
<b>@import "extra.css" "Yellow Fish";</b>
@import "deco-a.css" "Budapest";
@import "deco-b.css" "Budapest";
<b>@import "common2.css";</b>
</pre>
</div>
<div class=example>
<p>If the user has chosen the “Simple” style, only
“Simple” and the nameless ‘<code
class=css>@import</code>’s (all shown in <code><b>bold</b></code>)
are used, the others are skipped:
<pre>
<b>@import "common1.css";</b>
@import "yellowfish.css" "Yellow Fish";
<b>@import "simple.css" "Simple";</b>
@import "extra.css" "Yellow Fish";
@import "deco-a.css" "Budapest";
@import "deco-b.css" "Budapest";
<b>@import "common2.css";</b>
</pre>
</div>
<p>Style sheets are only imported if the media query on the ‘<code
class=css>@import</code>’ (if any) matches the media for which the
UA renders the document.
<p>If an ‘<code class=css>@import</code>’ is skipped, then all
‘<code class=css>@import</code>’s inside the style sheet it
points to are also skipped, no matter what their names.
<p>The list of alternative style sheets that the user can choose from
consists of:
<ul>
<li>any names in the document source itself (such as <code
class=html>title</code> attributes on <code class=html>link</code> and
<code class=html>style</code> elements in HTML and<code
class=xml>title</code> pseudo-attributes on <code
class=xml><?xml-stylesheet?></code> instructions),
<li>the names of ‘<code class=css><a
href="#media">@media</a></code>’ and ‘<code
class=css>@import</code>’ rules that occur in linked style sheets
that don't have a name on the link, and
<li>the names of ‘<code class=css><a
href="#media">@media</a></code>’ and ‘<code
class=css>@import</code>’ rules that occur in style sheets linked
from ‘<code class=css>@import</code>’ rules that have no
name, recursively.
</ul>
<p>I.e., the UA must not look for additional names by following links with
a <code class=html>title</code> attribute or named ‘<code
class=css>@import</code>’ rules.
<p class=note>HTML <a href="#HTML401"
rel=biblioentry>[HTML401]<!--{{HTML401}}--></a> uses the term <dfn
id=preferred>preferred style sheet</dfn> for the named style sheets that
the author marked as the default. In CSS, these are all style sheets whose
name is the first name to occur on any ‘<code
class=css>@import</code>’ or ‘<code class=css><a
href="#media">@media</a></code>’. <dfn id=alternate>Alternate style
sheets</dfn> are all other named style sheets. Finally, HTML calls style
sheets without a name <dfn id=persistent>persistent style sheets</dfn>,
because they are imported together with the preferred ones as well as with
any alternatives.
<p class=note>The UA should not only provide the user with a choice of
alternative style sheets, but should also allow the user to turn all style
sheets off. <!-- See <span class=issue>[where?]</span>-->
<p class=issue>Are names matched case-sensitively or case-insensitively?
Property names and font names are case-insensitive, so it is probably most
consistent to treat style sheet names the same way.
<p class=issue>Would it be easier to read if we precede the name with a
keyword or some punctuation? E.g., ‘<code class=css>@import
url(foo.css) as "Boxed"</code>’.
<p class=issue>[When this section is rewritten to define user agent
conformance more clearly, it should state that (1) the media list
specified in an @import rule prevents the import from being processed if
the medium doesn't match, but it doesn't "associate" the media with the
style sheet so that it can't be imported some other way. (2) @import
without a medium must ignore any medium specified for the same style sheet
in a link from a document.]
<h2 id=at-media-rule><span class=secno>4. </span>Named <code><a
href="#media">@media</a></code> rules</h2>
<p>An <dfn id=media>@media</dfn> rule specifies the target media types
(separated by commas) of a set of rules (delimited by curly braces). The
‘<code class=css><a href="#media">@media</a></code>’ construct
allows style sheet rules for various media in the same style sheet:
<div class=example>
<pre>
@media print {
body { font-size: 12pt; }
h1 { font-size: 24pt; }
}
@media screen and (color) {
body { font-size: medium; }
h1 { font-size: 2em; }
}
@media screen, print {
body { line-height: 1.2; }
}
</pre>
</div>
<p>The full syntax of the expressions after ‘<code class=css><a
href="#media">@media</a></code>’ is defined by the Media Queries
specification <a href="#MEDIAQ"
rel=biblioentry>[MEDIAQ]<!--{{!MEDIAQ}}--></a>.
<p>After the media queries, before the "{", there may be a string that
assigns a name to the ‘<code class=css><a
href="#media">@media</a></code>’ rule.
<div class=example>
<pre>
@media all "Ultra blue" {
body { background: blue }
h1 { color: cyan }
}
@media screen, print "Simple and light" {
body { background: white; color: #333 }
h2 { font-size: bigger }
}
</pre>
</div>
<p>All ‘<code class=css><a href="#media">@media</a></code>’
rules with a name, together with any ‘<code
class=css>@import</code>’ rules with the same name, present
alternative style sheets. The UA must read the rules inside some
‘<code class=css><a href="#media">@media</a></code>’ rules and
skip others, as follows:
<ul>
<li>
<p>If the user has not chosen a style by name, the UA must read all
‘<code class=css><a href="#media">@media</a></code>’ rules
of which (1) the media query matches the UA and (2) that either have no
name or whose name is equal to that of the first named ‘<code
class=css>@import</code>’ or the first named ‘<code
class=css><a href="#media">@media</a></code>’, whichever comes
first.
<li>
<p>If the user has chosen a style by name, the UA must read all
‘<code class=css><a href="#media">@media</a></code>’ rules
(1) of which the media query matches the UA and (2) that either have no
name or whose name is equal to the user's chosen name.
</ul>
<div class=example>
<p>If the user wants the UA to use the default style, the following
example results in the UA reading the “Reverse video” style,
the unnamed ‘<code class=css><a
href="#media">@media</a></code>’ rule and all rules that are not in
any ‘<code class=css><a href="#media">@media</a></code>’ (all
shown in <code><b>bold</b></code>). We assume the UA uses the
‘<code class=css>screen</code>’ media.
<pre>
<b>body { background: white }</b>
<b>p { text-indent: 2em }</b>
<b>@media screen {
h1 { font-size: xx-large }
}</b>
<b>@media screen "Reverse video" {
body { background: black; color: white }
}</b>
@media screen, print "Rainbow style" {
p { color: #E0D }
}
</pre>
</div>
<div class=example>
<p>If the user wants the UA to use the “Rainbow style” style,
the following example results in the UA reading the “Rainbow
style” ‘<code class=css><a
href="#media">@media</a></code>’ rule, the unnamed ‘<code
class=css><a href="#media">@media</a></code>’ rule and all rules
that are not in any ‘<code class=css><a
href="#media">@media</a></code>’ (all sh
8194
own in
<code><b>bold</b></code>). We assume the UA uses the ‘<code
class=css>screen</code>’ media.
<pre>
<b>@import url(base.css);</b>
@import url(altbase.css) "Reverse video";
<b>body { background: white }</b>
<b>@media screen {
h1 { font-size: xx-large }
}</b>
@media screen "Reverse video" {
body { background: black; color: white }
}
<b>@media screen, print "Rainbow style" {
p { color: #E0D }
}</b>
</pre>
</div>
<h2 id=cascading><span class=secno>5. </span>Cascading</h2>
<p>The purpose of cascading is to find one <dfn id=winning>winning
declaration</dfn> among the set of declarations that apply for a given
element/property combination.
<p>User agents must sort declarations according to the following criteria,
in order of importance:
<ol>
<li>Weight. In CSS3, the weight of a declaration is based on the origin of
the declaration and its marked level of importance. See <a
href="#computing-weight">Computing Weight</a> below for how to compute
the weight. The declaration with the highest weight wins.
<li>Specificity. The <a href="/TR/css3-selectors">Selectors module</a> <a
href="#SELECT" rel=biblioentry>[SELECT]<!--{{!SELECT}}--></a> describes
how to compute the specificity. The declaration with the highest
specificity wins.
<li>Order of appearance. The last declaration wins. Rules in imported
style sheets are considered to be before any rules in the style sheet
itself. Rules in two imported style sheets are considered to be in the
same order as the @import rules themselves.
</ol>
<p>The sorting process continues until one winning declaration is found.
<h2 id=inheritance><span class=secno>6. </span>Inheritance</h2>
<p>Inheritance is a way of propagating property values from parent elements
to their children. Inheritance means that the specified value of a given
element/property is copied from the parent element's computed value for
the same property.
<p>The root element, which has no parent element, inherits the initial
value of the property.
<p>The page box inherits from the inherits the initial value of the
property. Margin boxes inherit from the page pox.
<p>Pseudo-elements inherit according to a fictional tag sequence described
for each pseudo-element <a href="#SELECT"
rel=biblioentry>[SELECT]<!--{{!SELECT}}--></a>.
<p>Some properties are said to be <dfn id=inherited
title=inheritance>inherited</dfn>. This means that, unless a value is
specified for the element/property combination, the value will be
determined by inheritance.
<p>All properties accept the ‘<code class=css>inherit</code>’
value which explicitly specifies that the value will be determined by
inheritance. The ‘<code class=css>inherit</code>’ value can be
used to strengthen inherited values in the cascade, and it can also be
used on properties that are not normally inherited. If the ‘<code
class=css>inherit</code>’ value is set on the root element, the
property is assigned its initial value.
<h2 id=initial><span class=secno>7. </span>Initial value</h2>
<p>Each property has an <dfn id=initial0>initial value</dfn> which becomes
the specified value when cascading and inheritance does not yield a value.
Also, the initial value can be explicitly specified with the ‘<code
class=css>initial</code>’ keyword which all properties accept.
<h2 id=computing-weight><span class=secno>8. </span>Computing weight</h2>
<p>In order to sort declarations in the cascading process, the weight of a
declaration must be known. In CSS3, the weight of a declaration is based
on the origin of the declaration and its marked level of importance.
<p>CSS style sheets may have three different origins: author, user, and
user agent (UA).
<ul>
<li><strong>Author:</strong> The author specifies style sheets for a
source document according to the conventions of the document language.
For instance, in HTML, style sheets may be included in the document or
linked externally.
<li><strong>User:</strong> The user may be able to specify style
information for a particular document. For example, the user may specify
a file that contains a style sheet or the user agent may provide an
interface that generates a user style sheet (or behave as if it did).
<li><strong>User agent:</strong> <em>Conforming user agents</em> [add ref]
must apply a "default style sheet" (or behave as if they did) prior to
all other style sheets for a document. A user agent's default style sheet
should present the elements of the document language in ways that satisfy
general presentation expectations for the document language (e.g., for
visual browsers, the EM element in HTML is presented using an italic
font). See "Appendix D. Default style sheet for HTML 4" <a href="#CSS21"
rel=biblioentry>[CSS21]<!--{{CSS21}}--></a> for a recommended default
style sheet for HTML 4.0 documents.
</ul>
<p>Each CSS declaration can have two levels of importance: normal (which is
default) and important (which must be marked). The CSS3 syntax module <a
href="#CSS3SYN" rel=biblioentry>[CSS3SYN]<!--{{!CSS3SYN}}--></a> describes
how declarations are marked as important.
<p>The weight of style sheets from the various origins, in ascending order,
is:
<ol>
<li>User agent style sheets
<li>User normal style sheets
<li>Author normal style sheets
<li>Author important style sheets
<li>User important style sheets
</ol>
<p>By default, this strategy gives author declarations more weight than
those of the user. It is therefore important that the UA give the user the
ability to turn off the influence of a certain style sheet, e.g., through
a pull-down menu.
<p>Declarations in imported style sheets have lower weight than
declarations in the style sheet from where they are imported. Imported
style sheets can themselves import and override other style sheets,
recursively, and the same precedence declarations apply.
<p>If the user agent chooses to honor presentational hints from other
sources than style sheets, these hints must be given the same weight as
the user agent's default style sheet. This rule is intended for
presentational hints in HTML.
<p class=note>Note that non-CSS presentational hints had a higher weight in
CSS2.
<h2 id=conformance><span class=secno>9. </span>Conformance</h2>
<p>[TBD]
<h2 class=no-num id=acknowledgments>Acknowledgments</h2>
<p>David Baron contributed to thie specification.
<h2 class=no-num id=references>References</h2>
<h3 class=no-num id=normative-references>Normative references</h3>
<!--begin-normative-->
<!-- Sorted by label -->
<dl class=bibliography>
<dt style="display: none"><!-- keeps the doc valid if the DL is empty -->
<!---->
<dt id=CSS3SYN>[CSS3SYN]
<dd>L. David Baron. <a
href="http://www.w3.org/TR/2003/WD-css3-syntax-20030813"><cite>CSS3
module: Syntax.</cite></a> 13 August 2003. W3C Working Draft. (Work in
progress.) URL: <a
href="http://www.w3.org/TR/2003/WD-css3-syntax-20030813">http://www.w3.org/TR/2003/WD-css3-syntax-20030813</a>
</dd>
<!---->
<dt id=CSS3VAL>[CSS3VAL]
<dd>Håkon Wium Lie; Chris Lilley. <a
href="http://www.w3.org/TR/2006/WD-css3-values-20060919"><cite>CSS3
Values and Units.</cite></a> 19 September 2006. W3C Working Draft. (Work
in progress.) URL: <a
href="http://www.w3.org/TR/2006/WD-css3-values-20060919">http://www.w3.org/TR/2006/WD-css3-values-20060919</a>
</dd>
<!---->
<dt id=MEDIAQ>[MEDIAQ]
<dd>Håkon Wium Lie; Tantek Çelik; Daniel Glazman. <a
href="http://www.w3.org/TR/2007/CR-css3-mediaqueries-20070606"><cite>Media
Queries.</cite></a> 6 June 2007. W3C Candidate Recommendation. (Work in
progress.) URL: <a
href="http://www.w3.org/TR/2007/CR-css3-mediaqueries-20070606">http://www.w3.org/TR/2007/CR-css3-mediaqueries-20070606</a>
</dd>
<!---->
<dt id=SELECT>[SELECT]
<dd>Daniel Glazman; Tantek Çelik; Ian Hickson. <a
href="http://www.w3.org/TR/2005/WD-css3-selectors-20051215"><cite>Selectors.</cite></a>
15 December 2005. W3C Working Draft. (Work in progress.) URL: <a
href="http://www.w3.org/TR/2005/WD-css3-selectors-20051215">http://www.w3.org/TR/2005/WD-css3-selectors-20051215</a>
</dd>
<!---->
</dl>
<!--end-normative-->
<h3 class=no-num id=other-references>Other references</h3>
<!--begin-informative-->
<!-- Sorted by label -->
<dl class=bibliography>
<dt style="display: none"><!-- keeps the doc valid if the DL is empty -->
<!---->
<dt id=CSS21>[CSS21]
<dd>Bert Bos; et al. <a
href="http://www.w3.org/TR/2007/CR-CSS21-20070719"><cite>Cascading Style
Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 19 July
2007. W3C Candidate Recommendation. (Work in progress.) URL: <a
href="http://www.w3.org/TR/2007/CR-CSS21-20070719">http://www.w3.org/TR/2007/CR-CSS21-20070719</a>
</dd>
<!---->
<dt id=CSS3PAGE>[CSS3PAGE]
<dd>Håkon Wium Lie; Melinda Grant. <a
href="http://www.w3.org/TR/2006/WD-css3-page-20061010"><cite>CSS3 Module:
Paged Media.</cite></a> 10 October 2006. W3C Working Draft. (Work in
progress.) URL: <a
href="http://www.w3.org/TR/2006/WD-css3-page-20061010">http://www.w3.org/TR/2006/WD-css3-page-20061010</a>
</dd>
<!---->
<dt id=HTML401>[HTML401]
<dd>Dave Raggett; Arnaud Le Hors; Ian Jacobs. <a
href="http://www.w3.org/TR/1999/REC-html401-19991224"><cite>HTML 4.01
Specification.</cite></a> 24 December 1999. W3C Recommendation. URL: <a
href="http://www.w3.org/TR/1999/REC-html401-19991224">http://www.w3.org/TR/1999/REC-html401-19991224</a>
</dd>
<!---->
</dl>
<!--end-informative-->
<h2 class=no-num id=index>Index</h2>
<!--begin-index-->
<ul class=indexlist>
<li>Alternate style sheets, <a href="#alternate" title="Alternate style
sheets"><strong>#</strong></a>
<li>alternative style sheets, <a href="#alternative" title="alternative
style sheets"><strong>#</strong></a>
<li>conditional import, <a href="#conditional" title="conditional
import"><strong>#</strong></a>
<li>‘<code class=css>@import</code>’, <a href="#import"
title="'@import'"><strong>#</strong></a>
<li>inheritance, <a href="#inherited"
title=inheritance><strong>#</strong></a>
<li>initial value, <a href="#initial0" title="initial
value"><strong>#</strong></a>
<li>@media, <a href="#media" title="@media"><strong>#</strong></a>
<li>media-dependent import, <a href="#conditional" title="media-dependent
import"><strong>#</strong></a>
<li>persistent style sheets, <a href="#persistent" title="persistent style
sheets"><strong>#</strong></a>
<li>preferred style sheet, <a href="#preferred" title="preferred style
sheet"><strong>#</strong></a>
<li>winning declaration, <a href="#winning" title="winning
declaration"><strong>#</strong></a>
</ul>
<!--end-index-->
<h2 class=no-num id=property-index>Property index</h2>
<!--begin properties-->
<table class=proptable>
<thead>
<tr>
<th>Property
<th>Values
<th>Initial
<th>Applies to
<th>Inh.
<th>Percentages
<th>Media
<tbody>
</table>
<!--end properties-->