Yes, that’s true, but the tests are meant to find which elements you’ve learned and applied. In your case, even though it’s at the top it’s not the right way to do it:
First of all, your navbar reference, on the CSS, is wrong. It should be #navbar, since the nav element has an id attribute with value of navbar.
The expected way to do it is to add a position fixed to the navbar:
#navbar {
position: fixed;
top: 0;
left: 0;
width: 100%; /* without this, the navbar will shrink */
}