What is this white bar on top of my navigation?

it has been there for a day but I’ve tried to remove it but it’s not working.

you have a padding: 20px in your container class, that’s the white line.

And you have declared the container class two times with different properties… that’s what is causing the issue.

Try putting some height and background in your container class same as your header in your CSS. And the background color put !important at the end to make sure it is executed.