Regex To Get Class Names From CSS 2.0

I have just read part of the CSS 2.0 spec and to tie in with one of my side projects about creating a CSS 2.0 parser in c#, I have created a regex [based off the spec] that should find all the class names in a CSS file.

.[-]?[_a-zA-Z][_a-zA-Z0-9-]|[^\0-\177]\[0-9a-f]{1,6}(\r\n[ \n\r\t\f])?|\[^\n\r\f0-9a-f]*

I intend to create more regex's over the next few days to parse all the other elements that appear inside the CSS spec. Then once these are done I should be able to have a stab at creating a full CSS 2.0 parser.