If you're looking for world-class CSS knowledge, start with https://every-layout.dev; if you build UI for a living and haven't encountered axiomatic css and layout primitives, they're likely to change your world.
That's a radically misleading comment. It covers much more than layout, and the free content on the site is incredibly helpful and compelling. The full version more than justifies its price. And they offer it for free to students or anyone else for whom the cost is a problem (relying on the honor system).
It's far and away the best resource on CSS I've encountered in my 22-year career working with web technology for a living.
Ok,I missed that the honor system closed recently - but they continue to give it away freely to students or those facing hardship, on request.
The focus of course is on layout (by far the hardest part of CSS to get right), but it's in the context of building up your entire UI from robust, composable, accessible, standards-compliant, profoundly well-engineered primitives, based on first principles -- which principles are clearly articulated and demonstrated in the site.
It also covers typography (IMO by far the best explanation I've encountered of _why_ to use a typographic scale as the foundation of your design system), as well as touching on things like web components, shadowDOM, custom properties.. . and providing a deeply-expert perspective on the relative merits of utility classes (a la Tailwind et al), among other approaches.
I've been working in web-related roles for a living for over 20 years and have never once encountered a CSS-related resource that was this compelling and useful.
"Can't find TOC"?
Um, it's in the site's primary navigation, in the left column. Literally impossible to miss.
I paid the full $100 and was glad to do so. The authors aren't popular (they've clashed on twitter with some big-name FE people like MDalgleish) but their ideas and body of work are unparalleled, and that's what I support.
If I were more selfish I might try to keep my newfound FE superpowers [axiomatic css and composable layout primitives are transformational] a secret, but I find myself wanting to spread the word and support https://every-layout.dev every chance I get.
