Add better docs and guides

Would be nice to know the best practices and other ideas behind the lib, instead of making big mistakes.
- For example how to handle dynamic css?
- When to inject? Load all modules and then run inject? (then how about dynamic, look up)
- Add links to open source projects that are using;
- Show more example;

Start by reviewing the existing documentation and usage examples for the library, then identify what guidance is missing. The requested outcome is a set of best-practice guides covering dynamic CSS, injection timing, module loading, links to projects using the library, and additional examples; the issue does not name specific files or tests.

Written by the indexing model from the issue text.