* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #111;
  overscroll-behavior: none;
  position: fixed;
  top: 0;
  left: 0;
}
canvas { display: block; touch-action: none; }