html,
body {
  width:100%;
  height:100%;
  margin:0;
  padding:0;
}

body {
  display:flex;
  justify-content:center;
  align-items:center;
  background-color:#1a1a1a;
}

canvas {
  visibility:hidden;
  border: 20px solid #ddd;
  border-radius: 10px;
}