Umm, what skin are you using, in the defaul skin (monobook) Article space is a white background, everything else is light blue last I checked.
I can't see any difference at all, even when I'm looking for it. I'm using monobook and don't seem to have any custom css at all (I thought I did, but it must all be js instead), so if it's there, I would expect to see it...