[tuyiown]

> Shouldn't the drawing layer be concerned with drawing primitives?

CSS is not a drawing layer. The drawing is driven by the DOM, either setup by HTML or updated through JS. CSS only piggyback on it by giving parameters to the painting engine about what to do with dom, essentially overriding the defaults parameters. You can add dom blocks, modify positioning behavior with complex algorithms, even margins are not really trivial.

I don't think this is a great solution, but people started this to be able to modify colors during dom rendering without having to update their HTML code, probably because updating HTML code was not fun at all, but I really think the wrong problem was addressed. Those were the «webmaster» times, so there's also that.