@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
  .products-panel { order: 1; }
  .order-panel { order: 2; }
}
@media (max-width: 640px) {
  .app-shell { padding: 10px; }
  .topbar { flex-direction: column; align-items: flex-start; gap: 10px; }
  .product-grid { grid-template-columns: 1fr; }
  .section-head, .inline-actions { flex-direction: column; align-items: stretch; }
  .top-actions { width: 100%; }
  .top-actions button { flex: 1; }
}