html,
body {
  margin: 0;
  height: 100%;
  width: 100%;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  background: #000;
  overflow: hidden;
  min-height: 100vh;
}

canvas {
  width: min(100vw, calc(100vh * 4 / 3));
  height: min(100vh, calc(100vw * 3 / 4));
  display: block;
}