Use of position: fixed render links unclickable

Hi first time poster here. I am currently working through the Technical Documentation Project and I am trying to create the fixed navbar that is required in the specification. When I add “position: fixed” to my navbar element the anchor tag links within said navbar are unresponsive. I have tried using z-index on the navbar element but nothing changes. I have provided a link to my CodePen below. Any help would be appreciated.