When I scroll down with a mouse,
YouTube video covers the Header.
I found error on " position: relativee; ".
I changed to " position: relative; ",
but it's still unresolved.
So, I deleted it.
I deleted "position: relative;".
Also, I changed "width" and
"height".
Now, It works well with the changed codes.
YouTube video does not cover the Header when scrolling down with a mouse.
