*{margin:0;padding:0;box-sizing:border-box}
  html,body{height:100%;background:#000;overflow:hidden}
  canvas{display:block;width:100vw;height:100vh}
  #hint{position:fixed;left:50%;bottom:18px;transform:translateX(-50%);
    font-family:system-ui,sans-serif;font-size:12px;color:rgba(255,255,255,.45);
    letter-spacing:.04em;pointer-events:none;transition:opacity .6s}