Yes! I strongly recommend to learn the fundamentals of web development and the basics of HTML, CSS, and JavaScript. At least if you are pursuing a career on web development. Learning CSS makes you a better Tailwind developer too.
HTML is ok, you don't have that many elements anyway. JS is fine too, learning the basics of OOP and any imperative language compounds. But css? oh boy. It feels like a Frankenstein monster where each improvement comes with its new set of ad-hoc features. `grid-template-rows: masonry;` wtf is even that?!
I agree. It's a super weird "language". There are flaws of course, like the grid syntax is a bit wild. But love the very basics: the cascade, the selectors, and the ability to separate styling from the structure.