html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

#sky {
  background: -webkit-linear-gradient(#00111e 30%, #033d5e);
  background: -moz-linear-gradient(#00111e 30%, #033d5e);
  background: -o-linear-gradient(#00111e 30%, #033d5e);
  background: linear-gradient(#00111e 30%, #033d5e);
  overflow: hidden;
}