body {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-family: sans-serif;
  background: #222;
  color: #eee;
  margin: 0;
  padding: 0;
  height: 100vh;
}
#controls {
  margin: 10px;
}
canvas {
  border: 1px solid #555;
}