*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

.zh { display: inline; } .en { display: none; }
body.en-mode .zh { display: none; } body.en-mode .en { display: inline; }
div.zh { display: block; } div.en { display: none; }
body.en-mode div.zh { display: none; } body.en-mode div.en { display: block; }

#bg-canvas {
  position: fixed; inset: 0; z-index: -1;
  pointer-events: none;
}