The CSS3 Selectors module and CSS3 Namespaces module

The CSS3 Selectors module and CSS3 Namespaces module have both been released as official W3C recommendations, becoming the second and third CSS3 modules, respectively, to reach the end of the development cycle, following on from the release of the CSS3 Color module as a W3C recommendation earlier this year.

According to a post on the CSS Working Group’s blog:

Today W3C issued two new Recommendations: Selectors Level 3 and it dependency, CSS Namespaces. Selectors Level 3 has been a core part of CSS for awhile now, and is interoperably implemented by all modern browsers (including IE as of IE9). CSS Namespaces, which allows namespace-specific selectors, just completed its PR review phase, allowing both it and Selectors Level 3 to progress to W3C Recommendation.

The finalized specifications can be found here:
Selectors Level 3 – W3C Recommendation
CSS Namespaces – W3C Recommendation