There's more than a couple CSS tutorials that I would recommend.
In particular, it may be a bore, but Jonas Schmedtmann's advanced css and scss course covers more than just the basics; more importantly, the course goes over CSS architecture and how to compose reusable components from scratch. It does gloss over the basics, but what do you expect from an advanced course.
This course along with my own personal projects really helped me make better, more meaningful CSS decisions as a developer rather than making decisions in what seems like a vacuum.
I was going to recommend Jonas Schmedtmann's Advanced CSS course but you already did. It's amazing!
He also has this course that you can take before the advanced one if needed... I haven't taken it but I'm tempted to. udemy.com/design-and-develop-a-kil...
That's a good one too. It really goes to show that being a 'full stack' developer tends to leave a tremendous deficit in other areas of expertise.
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