body {
  background:black;
  background:white;
}


button {
  position:fixed;
  top:2em;
  left:2em;
}

.overlay{
  position: fixed;
    height: 100vh;
    width: 50vw;
    top:0;
    left:0;
    background: rgba(0,0,0,.15);
    z-index: 100;
    backdrop-filter: blur(8px) contrast(2) brightness(2.5);

}

canvas{
  position:absolute;
  height:100%;
  width:100%;
  left:0;
  top:0;
}


div{
  position:fixed;
  background:white;
  padding:1em;
  left:0;
  top:0;
  color:black;
  z-index:500;
}