@media (max-width: 768px) {
  .section { padding: 50px 0; }
  .section-title h2 { font-size: 28px; }
  .hero { padding: 60px 0; }
  .hero h1 { font-size: 32px; }
  .cat-grid, .service-grid, .steps, .news-grid { grid-template-columns: 1fr; }
  .testimonial-grid { grid-template-columns: 1fr; }
  .strategy-list { columns: 1; }
  .topbar .container { justify-content: center; text-align: center; }
  .footer-grid { grid-template-columns: 1fr; }

  /* ====== 手机导航 ====== */
  .header-main { position: relative; }
  .header-main .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: nowrap;
  }
  .logo { flex-shrink: 1; }
  .logo img { height: 36px; }
  .menu-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--heading);
    cursor: pointer;
    flex-shrink: 0;
    z-index: 110;
  }
  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--white);
    flex-direction: column;
    max-height: 70vh;
    overflow-y: auto;
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
    z-index: 105;
    padding: 0;
    margin: 0;
    list-style: none;
  }
  .nav.nav--open {
    display: flex;
  }
  .nav > li {
    border-bottom: 1px solid var(--border);
    position: relative;
  }
  .nav > li > a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 20px;
    font-size: 15px;
    font-weight: 600;
    color: var(--heading);
    border-radius: 0;
  }
  .nav > li > a:hover {
    background: rgba(255,99,14,0.04);
    color: var(--primary);
  }
  /* 有子菜单的父级加箭头 */
  .nav > li.has-sub > a::after {
    content: '▸';
    display: inline-block;
    font-size: 12px;
    margin-left: 8px;
    transition: transform 0.25s;
  }
  .nav > li.has-sub.sub--open > a::after {
    transform: rotate(90deg);
  }
  /* 手机端子菜单：内嵌手风琴 */
  .nav .submenu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    border-radius: 0;
    background: var(--bg-light);
    padding: 0;
    min-width: auto;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }
  .nav .submenu.submenu--open {
    max-height: 600px;
  }
  .nav .submenu li {
    border-top: 1px solid rgba(0,0,0,0.04);
  }
  .nav .submenu li a {
    display: block;
    padding: 12px 20px 12px 36px;
    font-size: 14px;
    color: var(--text);
  }
  .nav .submenu li a:hover {
    background: rgba(255,99,14,0.06);
    color: var(--primary);
  }

  /* ====== 子頁面手機端 ====== */
  .page-hero { padding: 40px 0; }
  .page-hero h1 { font-size: 28px; }
  .page-hero .page-hero-sub { font-size: 15px; }
  .contact-form .form-row { grid-template-columns: 1fr; }
  .about-feature-grid { grid-template-columns: 1fr; }
  .choose-grid { grid-template-columns: 1fr; }
  .product-pricing { grid-template-columns: 1fr; }
  .pricing-card.featured { transform: none; }
  .pricing-card.featured:hover { transform: translateY(-4px); }
  .news-list-item { grid-template-columns: 1fr; }
  .news-list-img img { height: 180px; }
  .news-categories { gap: 6px; }
  .cat-tag { font-size: 12px; padding: 6px 12px; }
  .article-header h1 { font-size: 24px; }
  .article-section h2 { font-size: 20px; }
  .breadcrumb { font-size: 12px; padding: 10px 0; }
  .faq-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr; }
  .stat-num { font-size: 36px; }
  .link-types-grid { grid-template-columns: repeat(2, 1fr); }
  .slogan-text { font-size: 15px; }
  .about-img-row { flex-direction: column; align-items: center; gap: 16px; }
  .about-img-item { max-width: 100%; }
  .about-img-item.about-img-center { margin-top: 0; max-width: 100%; }
  .page-hero { padding: 40px 0; }
  .page-hero h1 { font-size: 28px; }
}