There's so many of these "just add water" little "semantic" CSS projects. Going through projects and seeing which are dead is always a chore. Maybe an AI scanning projects for "life" would be helpful?
I dug through a ton of these for several days before finally deciding to just make my own...
All the lesser known ones tend to not be very extensible or themable beyond basic color changes, and they're a little too extreme about pure semantic HTML.
This guy has a really good roundup with last commit and GitHub stars info:
I think CSS's standard hsl(…) did most of the heavy lifting here. Tailwind took advantage and set variations to CSS classes.
I am coming to prefer lch(…) to any library. It scratches that consistent color itch and has basically universal support now in browsers. Then again, I prefer setting my CSS values through CSS variables rather than setting visual styles in the markup. YMMV
I love PicoCSS as well, only combined with Svelte. My only complaint is that I also like OpenProps, and I truly wish OpenProps and PicoCSS would join forces with a common CSS variable API. It would help to bridge the gap between basic personal project and something noticeably bigger.