nav {
  position: absolute;
  top: 1rem;
  left: 1rem;
}
nav > a {
  display: block;
  width: 3rem;
  height: 3rem;
  background-color: var(--yellow);
  color: var(--green-darker);
  font-size: 1.5rem;
  line-height: calc(3rem - 0.25rem);
  text-align: center;
  border-radius: 0.5rem;
  border-bottom: 0.25rem solid var(--yellow-dark);
}