html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: #000; /* pure black */
  overflow: hidden;
  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
  touch-action: none; /* allow custom touch handling */
}

#game {
  display: block;
  width: 100vw;
  height: 100vh;
}