Nav bar should be at the top of the viewport, but isn't it already at the top?

I need to get the last error fixed to pass the challenge and that is to have the nav bar at the top of the viewport. But I think my navbar is already at the top of the screen on PC and mobile, so I’m not sure how to fix the issue.
Product Landing Page

It needs to stay at the top of the page. And it isn’t at the top either.

I have done what the lesson said. I added to .nav-link this position:fixed;, top:0px; and left:0px;. But it made the links disappear.

It would go on the #nav-bar not the .nav-link

Just so you know you can’t have your current design and pass the test.

Thank you, for your help!