Yes, it defines the structural bounds your CSS is able to manipulate. It doesn't dictate how it needs to be manipulated other than a rough idea about what things will render out in what order. (I'd hardly call that presentation)

The key point here is that CSS exists precisely because html markup isn't enough on its own to style itself. If it was, CSS wouldn't exist.

The idea that something like tailwind can come in with a bunch of fine grained CSS classes and solve this inate complexity is laughable at best and wildly unprofessional at worst.

It just shows a complete lack of understanding about what html is and isn't and why CSS even exists in the first place.

Fwiw, I get it. Tailwind is a neat shorthand script you can use to pump out trash you'll never look at again. For the rest of us doing actual work on things that we'll need to modify 6 months from now I'd much prefer something readable that I can actually have a hope of modifying even if a teammate wrote the thing.