body {
  margin: 0;
  padding: 0;
  }
html { position: absolute; left: 0;
    overflow-x: hidden;
    overflow-y: scroll; }
#myCanvas {
  display: block;
background: url('https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1545068816356&di=429afaf4a0a6fab7df05519bd7dac8a2&imgtype=0&src=http%3A%2F%2Fuploads.5068.com%2Fallimg%2F1712%2F74-1G221161949.jpg');
}