Remove fill on top of the logo

Hello,
I wanted to know how I can remove a fill that appears on the home page just above the logo.
To solve a little the problem of that initial space, we changed the color gray to white and raised the logo 40 px up.
The problem is that when we resize the page, that fill appears again.
I would also like you to tell me how I can eliminate that filling in mobile format.

Thank you very much.