What does . The navbar should always be at the top of the viewport. means in project 3

I completed 90% of my 3 rd project and I left one thing to pass all the test.
I don’t understand what. does The navbar should always be at the top of the viewport. means. to work.
here is my code. https://codepen.io/solomon123fgt/pen/VwLWGYO?editors=1000

Please Test my project and tell me how I will do the Remaining part I remain only one thing?

To set navbar always at the top of viewport you need to use position:fixed property to #nav-bar and then you will pass all the test

Thank you , it works