:root {
  --bg-color:#00FF00; /* green */
  --pg-color:#000000; /* black */
}


body {
  background: #000000;
  color: white;
  font-family: sans-serif;
  font-size: 0.875em;
  top:200px;
  left:700px;
  }

nav {
 background-color:var();
  top:100px;
  left:200px;
  width:120px;
  height:200px;
  z-index:9;
  font-weight: bold;
  font-size: 1.16em;
  color: green;
  }