The creators of Tailwind wrote the brilliant book "Refactoring UI" [0], which presents a systematic design system, introducing ideas such a type-scales, color-scales, spacing, and tactics to minimizes the cognitive burden on the designer by forcing design choices. The ideas presented in this book basically are tailwind classes!
When you build with Tailwind, everyone is speaking the same design language, and you end up with harmonious designs, even when components came from different projects or designers.
I disagree with the author's approach. It's basically just copying the utility classes from Tailwind and implementing them in an unergonomic way. Perhaps the best idea is component level CSS which is something that's been enabled by better tooling. I would implore anyone who doesn't really get Tailwind, to read the origin story [1].
[0] https://refactoringui.com/ [1] https://adamwathan.me/css-utility-classes-and-separation-of-...
Before Tailwind got big, Adam released an amazing book about UI/UX called Refactoring UI[0] and it really helped me become better and understand subtleties of design. I even considered printing a personal physical book for my coffee table. If you want to support Adam and don't need Tailwind Plus, this ebook could be a good way.
This book taught me so much about modern UI design. If you've ever tried building a component and thought to yourself, "hmm something about this looks off," you might benefit from this book.
These days some of the examples might be a little bit dated (fashions come and go), but the principles it teaches you are rock solid.