/* 手机端：屏幕宽度 ≤ 768px */
@media screen and (max-width: 768px) {
  html { font-size: 14px; }
  .category-bar { padding: .4rem 0; }
  .category-item { padding: .3rem .6rem; margin: 0 .4rem; }
  .category-header { font-size: 1.1rem; }
  .product-item { flex-direction: column; align-items: flex-start; padding: .6rem; }
  .product-item .name { margin-bottom: .4rem; font-size: .95rem; }
  .product-item .price { font-size: 1rem; }

  .bottom-sheet { border-radius: 12px 12px 0 0; }
  .sheet-header h3 { font-size: 1.1rem; }
  .sheet-price { font-size: 1.1rem; }
  .qty-control button { width: 2.4rem; height: 2.4rem; font-size: 1.4rem; }
  .qty-control span { font-size: 1.1rem; }

  .footer-bar { flex-direction: column; text-align: center; padding: .6rem; }
  .footer-bar > div { margin-bottom: .4rem; }
  .btn-submit { width: 100%; }
}

/* 超大屏：屏幕宽度 ≥ 1200px */
@media screen and (min-width: 1200px) {
  main { max-width: 1140px; margin: 0 auto; }
  .category-bar { max-width: 1140px; margin: 0 auto; }
  .footer-bar { max-width: 1140px; margin: 0 auto; }
}