html,body{
  height: 100%;
  width: 100%;
  margin: 0;
}
#cover{
  height: 100%;
  width: 100%;
  overflow: hidden;
  text-align: center;
  position: relative;
  background-size: cover;
  background-attachment: fixed;
}
Cover take 100% of landing view
Cover take 100% of landing view
