html, body {
  width: 100%;
  height: 100%;
  margin:0;
  padding:0;
  background-color: #F2F0F0;
  justify-content: center;
  align-items: center;
  display: flex;

  /* leave it to hide the scrollbars */
  overflow: hidden;
}

canvas {
  max-width:100%;
  max-height:100%;
  margin:auto;

  overflow:auto;
  object-fit:contain;

  position:fixed;
  top:0;
  bottom:0;
  left:0;
  right:0;
}