html,
body {
  height: 100%;
  width: 100%;
  overflow: hidden;
}
#content {
  z-index: 2;
  position: absolute;
  top: 0;
  bottom: 0;
  opacity: 0.8;
  -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=80)";
  filter: alpha(opacity=80);
  transition: all 0.5s ease-in-out;
}
#music {
  z-index: 1;
  height: 100%;
  width: 100%;
}