I just checked, and no it doesn't. The icons in the navigation are separate .gif files.
edit to add: And this makes a large part of the load time (when not cached). Other than that, the largest part is the SSL handshake and the fact that the server seems to be a bit slow (WRT the fact that it serves static content; 200ms for dynamic stuff would be okay).
Still a lot faster than most of todays websites.
