* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; overflow: hidden; background: #07070c; font-family: system-ui, sans-serif; }
canvas { display: block; width: 100%; height: 100%; touch-action: none; }
.demo-hud {
  position: fixed; left: 16px; bottom: 16px; z-index: 2;
  padding: 10px 14px; border-radius: 12px;
  background: rgba(10, 10, 16, 0.72); border: 1px solid rgba(99, 102, 241, 0.35);
  color: #e2e8f0; font-size: 12px; line-height: 1.5; backdrop-filter: blur(8px);
  pointer-events: none; max-width: min(360px, 90vw);
}
.demo-hud strong { color: #a5b4fc; font-weight: 650; }
.demo-title {
  position: fixed; left: 16px; top: 16px; z-index: 2;
  font-size: 13px; font-weight: 650; color: rgba(255,255,255,.85);
  letter-spacing: .04em;
}