Copy-paste the following into the bottom of all applicable stylesheets:

  z-index: 99;
  background-color: yellow;
  padding: 6px;
  display: flex;
  justify-content: space-around;
  align-items: center;

  background-color: white;
  display: block;
  width: 100px;
  padding: 5px;
  margin: 8px 5px 8px;

Now, I don't know if you noticed, but as-is this is a really ugly navbar. PLEASE change the width, height, colors, link styling, outline, and other settings to taste.