body {
  background-color: #111;
  color: white;
  font-family: sans-serif;
  text-align: center;
}

h1 {
  text-align: center;
  margin: 0;
}

canvas {
  display: block;
  margin: 0 auto;
}

input[type="range"] {
  width: 300px;
  height: 50px;
}