/* 预加载动画 - React 渲染前显示，消除白屏 */
#preloader {
  position: fixed; inset: 0; z-index: 9999;
  display: flex; align-items: center; justify-content: center;
  background: #f8fafc; transition: opacity 0.3s ease;
}
#preloader.done { opacity: 0; pointer-events: none; }
#preloader .spinner {
  width: 36px; height: 36px;
  border: 3px solid #e2e8f0;
  border-top-color: #6366f1;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }