CSS _ why does it go over the fixed bar? Help

Question

Welcome-
I made this website a while ago. And I notice the Welcome block is still not fixed.
It goes over the top fixed bars. Which it shouldn't.
It's supposed to go under the top fixed bars like the other contents.
I tried (position + Z-Index, but didn't work for me)

Can someone help me make it stop going over the top fixed bars and make it go under the top fixed bars mm?

https://code.sololearn.com/WBiuSspkRdhY/?ref=app

Thx!

Answer 1

Ginfio I just add higher z-index to the fixed bar

Answer 2

https://code.sololearn.com/Wl6XPxoxcPGN/?ref=app

Answer 3

Calviղ can you tell me what you changed in that code please?