html, body {
  margin: 0;
  padding: 0;
  background: #000;
  overflow: hidden;
  font-family: monospace;
}

canvas {
  display: block;
  background: #111;
}

#controls {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  text-align: center;
}

#controls button {
  width: 64px;
  height: 64px;
  margin: 6px;
  font-size: 24px;
  border-radius: 12px;
  border: none;
  background: #222;
  color: #0f0;
}

#controls button:active {
  background: #0f0;
  color: #000;
}