W3C Invites Implementations of CSS Conditional Rules Module Level 3, and CSS Values and Units Module Level 3

The Cascading Style Sheets (CSS) Working Group invites implementation of two Candidate Recommendations:

• CSS Conditional Rules Module Level 3. This module contains the features of CSS for conditional processing of parts of style sheets, conditioned on capabilities of the processor or the document the style sheet is being applied to. It includes and extends the functionality of CSS level 2], which builds on CSS level 1. The main extensions compared to level 2 are allowing nesting of certain at-rules inside ‘@media’, and the addition of the ‘@supports’ rule for conditional processing.
• CSS Values and Units Module Level 3. This CSS3 module describes the common values and units that CSS properties accept and the syntax used for describing them in CSS property definitions. This is an update that clarifies that the viewport size used by the 'vw' and 'vh' units includes the size of any scrollbars only when the scrollbars are “automatic” (CSS rule 'overflow: auto'), and that the corresponding definition of viewport size for paged media is *not* part of this module.

Learn more about the Style Activity.