I've reverted r17507 and r17518 after getting massive complaints immediately after they went live in today's site update.
I'd like to ask that people please try to refrain from changing core styles like this without testing it against the actual site usage; for instance the prominent main pages of English and German Wikipedia and their site-specific CSS/JS.
We've gone through this dance enough times in the last few weeks I think we should all be able to realize that it's kind of disruptive and should be avoided.
-- brion vibber (brion @ pobox.com)