The more I think about it, the more certain I become that immutable constants (a good idea, IMO) are the furthest CSS could safely go down the rabbit hole before the entire enterprise would consume itself in spaghetti-code madness.

Not that plenty about CSS doesn't beg for better abstractions, but turning it into a programming language is kind of a terrifying prospect. I've see too much of what enthusiastic amateurs can inflict with JavaScript.