Are you still skeptical about TypeScript? If that's the case then this post will help you make an informed decision.
Redux open-source repository is one of the most beautiful well-documented beginner-friendly TypeScript codebase
Before you complain about CSS problems at scale or request new features, you should read the design principles behind it
Currently CSS versioning is a mess with countless separate modules, CSS3 literally refers to anything beyond CSS2.1, and there is no such thing as CSS4
Being able to process and transform CSS before running in browser is powerful and open to a lot of possibilities
Starting out with mostly latest cutting-edge CSS features then adding fallbacks gracefully
Starting out with mostly basic widely-supported CSS features, then adding newer ones if supported progressively