margin: 0;

  padding: 0;

}

canvas {

  display: block;

}

​

​

/* GH: added */

​

#canvasContainer {

  margin: calc(50vh - 200px) auto 0 auto;

  width: 400px;

  position: relative;

}

​

#controls {

  position: absolute;

  top: -20px

}