* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  width: 100%; height: 100%; overflow: hidden;
  background: #2b1d0e;
  touch-action: none;
  -webkit-user-select: none; user-select: none;
}
canvas {
  display: block;
  width: 100%;
  height: 100%;
  cursor: crosshair;
}