html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #111;
  font-family: system-ui, sans-serif;
}
#app {
  width: 100vw;
  height: 100vh;
}
canvas {
  display: block;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at top, #20242b, #0f1115 72%);
}