header {
  text-align: center;
  background: #5178d5;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 999;
}
header a {
  display: inline-block;
  font-size: 2.4rem;
  font-weight: 600;
  padding: 2rem;
  color: #fff;
}

main {
  margin-top: 6.4rem;
  padding: 3rem 2rem;
}