header {
  align-items: center;
  display: flex;
  height: 10vh;
  justify-content: center;
  position: absolute;
  width: 100%;
}

header > nav > a {
  border-radius: 15px;
  color: #f5f5f5;
  font-size: 1rem;
  font-weight: 700;
  padding: 1rem;
  text-decoration: none;
  text-transform: uppercase;
  transition: 
    background-color 300ms ease-in-out,
    color 300ms ease-in-out;
}

header > nav > a:hover {
  background-color: #67aeef; 
}

@media (max-width: 600px) {
  header {
    display: none;
  }
}