- From: L. David Baron <dbaron@dbaron.org>
- Date: Fri, 2 Sep 2011 15:11:23 -0700
- To: www-style@w3.org
http://www.w3.org/TR/2011/WD-css3-conditional-20110901/ has been published as the first public working draft of the CSS Conditional Rules Module. To quote from its introduction: CSS 2.1 defines one type of conditional group rule, the ‘@media’ rule, and allows only rulesets (not other @-rules) inside of it. The ‘@media’ rule provides the ability to have media-specific style sheets, which is also provided by style sheet linking features such as ‘@import’ and <link>. The restrictions on the contents of ‘@media’ rules made them less useful; they have forced authors using CSS features involving @-rules in media-specific style sheets to use separate style sheets for each medium. This specification extends the rules for the contents of conditional group rules to allow other @-rules, which enables authors to combine CSS features involving @-rules with media specific style sheets within a single style sheet. This specification also defines additional types of conditional group rules, ‘@supports’ and ‘@document’, to address author and user requirements. The ‘@supports’ rule allows CSS to be conditioned on implementation support for CSS properties and values. This rule makes it much easier for authors to use new CSS features and provide good fallback for implementations that do not support those features. This is particularly important for CSS features that provide new layout mechanisms, and for other cases where a set of related styles needs to be conditioned on property support. The ‘@document’ rule allows CSS to be conditioned on the page to which the style sheet is being applied. This allows users to apply styles to a particular page or group of pages, which greatly increases the power of user style sheets. The CSS working group welcomes comments on this specification. The preferred place for them is this mailing list, <www-style@w3.org>. Please start the subject line of your message with [css3-conditional], as I did in this message. (But please start a new thread for each topic rather than responding to this one.) Note these three different URLs for this specification: http://www.w3.org/TR/2011/WD-css3-conditional-20110901/ is a permanent archive of the version published yesterday as a W3C technical report. http://dev.w3.org/csswg/css3-conditional/ is the editor's draft, which will be updated most promptly in response to feedback. http://www.w3.org/TR/css3-conditional/ is the most recent version published as a W3C technical report, which will be updated much less frequently: when the working group wishes to solicit wider feedback or advance this document on the W3C Recommendation track. -David -- 𝄞 L. David Baron http://dbaron.org/ 𝄂 𝄢 Mozilla Corporation http://www.mozilla.com/ 𝄂
Received on Friday, 2 September 2011 22:11:55 UTC