I dont see grid and flexbox on the css course, is there any?

Answer 1

Can't say for sure, but if you haven't seen any there mightn't be any. These courses are very elementary, not all aspects of a language are covered. Might be that more advanced techniques are taken on in courses about responsive web design or any of the other web based courses.

Answer 2

There are some user-made tutorials and examples you can find on the Code Playground. You can take a lot of inspiration by checking other people's codes.
https://code.sololearn.com/WhCWm0b7g1Qo/?ref=app
https://code.sololearn.com/WH67FTMsWZ4V/?ref=app