body {
  width: 100%;
  height: 100vh;
  background-color: #000;
  background-image: radial-gradient(circle at top right, rgba(121, 68, 154, 0.13), transparent), radial-gradient(circle at 20% 80%, rgba(41, 196, 255, 0.13), transparent);
}

canvas {
  position: fixed;
  width: 100%;
  height: 100%;
}