Make navigation bar fixed


I have a problem understanding how to make my navigation bar fixed so it appears always on the top of the viewport. My navigation bar includes the logo, title and links.

After trying to understand CSS position, reading some articles and watching some tutorials, I’m a bit stuck here and it’s the only test I can’t pass for the project. The only thing I need is the current design but with a fixed navbar.

This is the link to the project:

Thank you very much for your help!

You can do that with a fix position
Here’s how to

Yes, I know that, but I was asking for some help with my already written code since I’m not able to do it. If I apply position: fixed; to my navbar, everything becomes a mess even if I try to change the main content’s position values as well.