body,html {  
  margin: 0;
  overflow: hidden;
  padding: 0;
}
canvas {
  margin: auto;
  overflow: auto;
  position: fixed;
  object-fit: contain;
  transform: scale(0.9);
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  max-width: 100%;
  max-height: 100%;
}