/* ═══════════════════════════════════════════════
     RESPONSIVE
  ═══════════════════════════════════════════════ */
  @media (max-width: 1200px) {
    .product-grid { grid-template-columns: repeat(3, 1fr); }
  }

  @media (max-width: 900px) {
    .product-grid { grid-template-columns: repeat(2, 1fr); }
    .detail-hero, .detail-lower { grid-template-columns: 1fr; }
    .detail-title { font-size: 26px; }
    .carousel-wrap { aspect-ratio: 16/11; }
    .detail-lower { gap: 28px; }
    .usp-stack { flex-direction: row; flex-wrap: wrap; }
    .usp-card { flex: 1; min-width: 140px; }
  }

  @media (max-width: 640px) {
    /* hide desktop, show mobile */
    .site-header { display: none; }
    .site-footer .footer-inner { display: none; }
    .site-footer .footer-bottom { display: none; }
    .mobile-header { display: flex; }
    .mobile-filter-strip { display: flex; }
    .mobile-fab { display: flex; }
    .mobile-nav-drawer { display: block; }
    .mobile-footer { display: block; }

    .home-main { padding: 16px 12px; }
    .controls-row { display: none; }
    .product-grid {
      grid-template-columns: 1fr 1fr;
      gap: 10px;
    }

    .detail-main { padding: 16px 14px; }
    .back-btn { margin-bottom: 18px; }
    .detail-hero { gap: 20px; margin-bottom: 28px; }
    .carousel-wrap { aspect-ratio: 4/3; border-radius: var(--radius-sm); }
    .carousel-btn { width: 32px; height: 32px; }
    .detail-title { font-size: 22px; }
    .detail-price { font-size: 22px; }
    .detail-lower { gap: 20px; margin-bottom: 28px; }
    .usp-stack { flex-direction: column; }
    .purchase-section { padding: 22px 16px; margin-bottom: 28px; }
    .purchase-buttons { flex-direction: column; }
    .buy-btn { justify-content: center; }
    .footer-inner { grid-template-columns: 1fr; gap: 28px; padding: 40px 20px; }
    .footer-bottom { padding: 16px 20px; flex-direction: column; gap: 4px; text-align: center; }
  }