Position : sticky , align-items:center , justify-content: center not working on this program why?

Question

https://sololearn.com/compiler-playground/W1ebcHY9qjtJ/?ref=app

Answer 1

It works for me... The header div aligns the subheader div

Which is the problem? Can you specify where is the problem?

Answer 2

t
There is only 1 item in .Heading. How should it be aligned?

Answer 3

Align-items in . Heading section

Answer 4

maybe use
position:fixed;
instead.

Also, .box is the one that should be fixed, not .box1