> The point of CSS is specifically to separate styling and semantics, so that they are not tightly coupled.

That was the original point, and it turned out that nobody cares about that 99% of the time. It's premature optimization and it violates "YAGNI". And in addition to not being something most people need, it's just a pain to set and remember and organize class names and organize files.

Remember CSS Zen Garden from the late 90s? How many sites actually do anything like that? Almost none.

And the beauty of Tailwind is, when you actually do need themes, that's the only stuff you have to name and organize in separate CSS files. Instead of having to do that with literally all of your CSS.

Not only does no one care, but it's not even true. There are effects you simply cannot achieve without including additional elements. So separation of styling and sementics is dead on arrival.