Check out "Do you speak JavaScript?" - my latest video course on advanced JavaScript.
Language APIs, Popular Concepts, Design Patterns, Advanced Techniques In the Browser
CSS is easy? CSS is messy! And as a project grows, it only gets messier. You find yourself throwing !important at everything or fighting with long selectors just to get a style to overrule another. Projects eventually become unmanageable and you pray for the next redesign when you can burn it all down and start from scratch.