body {
  background-color: whitesmoke;
  overflow: hidden;
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
}

html,body {
  height: 100%;
}

canvas {
  display: block;
  max-width: 100%;
  max-height: 100%;
  bottom: 0;
  left: 0;
  margin: auto;
  overflow: auto;
  position: fixed;
  right: 0;
  top: 0;
  object-fit: contain;
}