The World Wide Web Consortium is already thinking about CSS4, Webmonkey reports. Yes, the newish CSS3 standards still aren’t supported by all browsers, but W3C is thinking ahead. The descriptions of the proposed changes are pretty tech-heavy. For example, David Storey pretty much blows my mind here:
There are three time-dimensional pseudo-classes:
:future. These relate to time related rendering (or time-dimensional canvas as the spec says), such as speech rendering of HTML documents (text to speech). The
:currentpseudo-class matches the element that is currently being rendered (such as styling the image that is currently being spoken). The
:pastpseudo-class styles matches elements that were rendered in the past (e.g have already been spoken), and
:futurematches elements that will be rendered in the future (will be spoken). There is also a version of
:currentthat takes arguments in parenthesis. This works in much the same way as the
:matches()pseudo-class, where it matches any of the comma separated selector compound selector strings.
If your brain can handle it, check out the working draft of CSS4 here.