Do you want to know how the CSS WG works? Fantasai has written about:csswg, An Inside View of the CSS Working Group at W3C.
It is now time to see if the specifications can be implemented. Large parts of both modules have already been implemented experimentally in various browsers and other software. Over the next six months, the working group plans to develop a test suite and then use the results of testing to decide if the specifications are ready to become W3C Recommendations.
Feedback on the specifications, in particular experience with implementing them, can be sent to the mailing list <firstname.lastname@example.org>. Please, include the short name of the specification between square brackets  in the subject of any message you send. That is: