Float the li elements left to line them up horizontally.
Style the links:
Set display to block.
Set padding to 1rem.
Set text-decoration to none.
Change the background when the links are hovered over.
Change the color when the links are clicked.
Notice that the white background seems to have disappeared. This is because we took the li elements out of normal flow. To get it back, use the ::after pseudo-element to add a cleared block pseudo-element at the end of the nav element: