How to change Nav Bar image

hi everyone, I'm trying to change my nav bar to an image, but my code doesn't seem to work for it . i heard this was the coreect code but it doesnt work for me

   . myspace-header .top-nav {

  background-image: url("https://files.catbox.moe/8unhhe.jpg");

  background-size: cover;

  background-repeat: no-repeat;

  background-position: center;

}

let me know what to do . thanks. i also changed the logo which worked, but this doesnt seem too . 

the key thing here is including !important for the nav background

(if you wanna see the code for it, it's still on that community build-a-blog thing you joined in on)