Where can I learn advance css (flexbox, grid etc.) I already learned basic

Answer 1

Unknown
Also check out https://css-tricks.com, they have many good tutorials and guides

Answer 2

MDN site may contain too much information, and also they use little complex words to explain topic.
I suggest you this:
https://www.w3schools.com/css/default.asp

But best is to check many resources, to understand better topic, and to fill gap you may have.

Don't forget to practice a lot, this is best way of learning.

Answer 3

You can always try by making some CSS projects of your own and experimenting with what you would like to learn and doing research alongside it.

Answer 4

Mozilla Developers Network (MDN) is a good place to learn advanced CSS