I'm delighted to announce that the MathML for CSS profile has been published as a W3C Recommendation.
http://www.w3.org/TR/2011/REC-mathml-for-css-20110607/
This had a dependency on CSS 2.1 which was also published today.
This completes the three REC-track documents produced by the MathML3-era Working Group, joining:
http://www.w3.org/TR/2010/REC-MathML3-20101021/
and
http://www.w3.org/TR/2010/REC-xml-entity-names-20100401/
The MathML for CSS profile (most of the technical work for which was done by George Chavchanidze of Opera) defines how a subset of MathML may be implemented using CSS. This is useful for two reasons: Firstly, it highlights possible places where CSS could be extended to improve its expressive power (so allowing a larger subset of MathML to be implemented) or secondly, it may be viewed directly as an implementation of a useful subset of MathML (and is similar to the CSS stylesheet for MathML which is used for MathML support in Opera). As usual, comments are welcome here or on www-math@w3.org list.