CSS is great, but its poorly taught. I've known so many developers of all skill levels who get stuck somewhere between "I can make it red but I have no idea how to apply all these random properties into the layout I want." They'd ask me for resources, and I couldn't find one I thought was very good at that.

So I tried to write one.

https://whatisjasongoldstein.github.io/buildcss/

What's nice about this is I wrote it for real people, tested it on them, applied their feedback... etc. It's a little old now (this was before widespread Flexbox support) but it's specifically aimed at the sorts of problems you described.