Just Thinking About CSS

Hey with all this talk/bullshit about CSS in design these days, why the hell doesnโ€™t someone try to standardize tag classes (to some extent)?

That way, we could allow our users to choose from a repository of designs, or at least we could re-use CSS from that repository ourselves, without changing our markup at all.

Surely someone has thought about this before? Is that sort-of what CSS Zen Garden is supposed to be?