http://www.w3.org/TR/2002/REC-xhtml1-20020801

Note section C.14 in particular. It's an interesting -- and practical -- change for all of us to be aware of in CSS.

I would post this in HTML instead, but because this has to do with an XML issue, it goes better here.

Other stuff on www.w3.org including CSS 2.1 Last Call.