W3C Invites Implementations of CSS Conditional Rules Module Level 3, CSS Cascading and Inheritance Level 4 and Level 5

The CSS Working Group invites implementations of the following three Candidate Recommendation Snapshots:

• CSS Conditional Rules Module Level 3 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 [CSS21], which builds on CSS level 1 [CSS1]. 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 Cascading and Inheritance Level 4 and CSS Cascading and Inheritance Level 5 describe how to collate style rules and assign values to all properties on all elements. By way of cascading and inheritance, values are propagated for all properties on all elements. New in Level 4 are the revert keyword and <supports-condition> for the @import rule. New in Level 5 is cascade layers.

CSS is a language for describing the rendering of structured documents (such as HTML and XML) on screen, on paper, etc.

Comments are welcome via the GitHub issues by 13 March 2022.