nav {
  background-color: #ccc;
  display: none;
  margin: 16px;
  padding: 16px;
  position: absolute;
  left: 0;
  right: 0;
  top: 70px;
  bottom: 0;
  z-index: 1;
}

nav.active {
  display: block;
}

nav ul {
  list-style-type: none;
  padding: 0;
}