header a {
  padding: 10px 20px;
  font-size: medium;
  cursor: pointer;
  border: none;
  background-color: #ffffff;
  text-transform: uppercase;
  text-decoration: none;
  color: #000000;
}
img {
  width: 100vw;
  height: 100vh;
  object-fit: cover;
  position: absolute;
  top: 0;
  left: 0;
  z-index: -1;
}