body {
  margin: 0;
  background: #f4f4f4;
  overflow: hidden;
  font-family: sans-serif;
}

canvas {
  display: block;
}

html, body {
  margin: 0;
  padding: 0;
  background: #000;
  width: 100%;
  height: 100dvh;    /* dynamic viewport height */
}

canvas {
  display: block;
  width: 100%;
  height: 100dvh;
  background: #000;
  touch-action: none;
}