My advice is to just learn a framework and let other people deal with the details. This article makes it seem like CSS is as easy to work with as pencil and eraser. But a lot of the complexity is arbitrary due to either history or fashion
CSS is super powerful and I love how much you can do with it. I’m still scratching the surface, too. I’ve been using it for years for common things as a full-stack dev but it’s only really the last six months that I’ve really begun to stretch myself with it.
The power it has for animations is impressive too, for example. I spent a lot of time on just that and flexbox and flexgrid and it made me go from hating CSS to really liking it.
I'm only now dipping my feet into front-end development, and I'm avoiding all frameworks[1], but to play with CSS I made this: https://rundata.co.za/~lelanthran/JustTryIt/
It's incomplete, it's not good for testing layouts, etc ... but it was useful to me when I didn't know what the defaults did.
(I should perhaps rewrite it now to be more complete and less cruft-filled - this was written when I knew less about JS and CSS than I do now).
[1] No special reason - there are too many, and most of them seem bloated for what I need. I'm sure react solves real problems, but I find it's shorter to solve my problems using whatever I've already written and understood than learning a whole new framework.
Enjoy the rewrite! I love that feeling of rewriting something with new knowledge and finding all kinds of gains while doing so.