CSS

html,body,div{
  margin: 0;
  padding: 0;
  width: 98%;
  height: 98%;
}
canvas{
    z-index: 0 !important;
}
audio{
  position: absolute;
  z-index: 2;
  top: 5px;
  right: 5px;
}
#debug{
  top: 5px;
  left: 5px;
  position: absolute;
  color: white;
  z-index: 3;
}
#skyday{position:absolute; left:0; top:0; z-index:-100; width:100%; height:100%;
    background-image: linear-gradient(bottom, rgb(218,237,255) 27%, rgb(30,153,235) 81%);
background-image: -o-linear-gradient(bottom, rgb(218,237,255) 27%, rgb(30,153,235) 81%);
background-image: -moz-linear-gradient(bottom, rgb(218,237,255) 27%, rgb(30,153,235) 81%);
background-image: -webkit-linear-gradient(bottom, rgb(218,237,255) 27%, rgb(30,153,235) 81%);
background-image: -ms-linear-gradient(bottom, rgb(218,237,255) 27%, rgb(30,153,235) 81%);

background-image: -webkit-gradient(
    linear,
    left bottom,
    left top,
    color-stop(0.27, rgb(218,237,255)),
    color-stop(0.81, rgb(30,153,235))
        );}

#skynight{position:absolute; left:0; top:0; z-index:-100; width:100%; height:100%;
    background: #080830; /* Old browsers */
background: -moz-linear-gradient(top, #080830 20%, #08162a 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(20%,#080830), color-stop(100%,#08162a)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, #080830 20%,#08162a 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, #080830 20%,#08162a 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, #080830 20%,#08162a 100%); /* IE10+ */
background: linear-gradient(to bottom, #080830 20%,#08162a 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#080830', endColorstr='#08162a',GradientType=0 ); /* IE6-9 */
}