html, body {
  margin: 0;
  padding: 0;
  background-color: black;
}
canvas {
  display: block;
  position:absolute;
  top:0;
  left:0;
  right:0;
  bottom:0;
  margin:auto;
  border: 10px solid white;
}

#canvas_container{
  width: 100vw;
  height: 100vh;
}