It's not one or the other. I learned CSS by learning Tailwind and using my IDE's preview feature to see what each class did (as well as reading articles, listening to podcasts, etc, but Tailwind was the foundation of my learning). The other day I wrote a tabbed view (like those widgets that show the same example in different programming languages) with 0 JavaScript, using some more advanced features like `:has()` and `nth-child()`.
Not asking for a cookie or anything, but just demonstrating that my understanding of CSS wasn't harmed by learning Tailwind. It was the best path for me as a beginner.
Picking colors I still struggle with. I struggle to find a middle ground between "all gray but readable" (which a client once called "depressing" and compared to Soviet block housing) and "hideously garish". Gray is, unironically, one of my favorite colors, but this view is not popular.