/* ==========================================================================
   Layout: Container, Header, Footer, Navigation
   ========================================================================== */

/* ---------- Container ----------
   流式 + 容器最大宽度 + 自适应内距：
   - 小屏（≤768px）：左右 20px 内距
   - 中屏：内距随视口扩张（4vw）
   - 大屏（>1500px）：内距封顶 60px
   - 超大屏（>1600px）：max-width 起作用，整个容器居中留白 */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(20px, 4vw, 60px);
}

.container-narrow { max-width: var(--container-narrow); }
.container-wide   { max-width: var(--container-wide); }

/* ---------- Top Bar (电话条) ---------- */
.top-bar {
  background: var(--color-primary-dark);
  color: rgba(255, 255, 255, 0.8);
  font-size: var(--fs-xs);
  padding: 6px 0;
}

.top-bar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.top-bar .welcome {
  letter-spacing: 0.5px;
}

.top-bar .contact-info {
  display: flex;
  gap: 20px;
  align-items: center;
}

.top-bar .contact-info span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.top-bar .contact-info .phone-small {
  color: var(--color-accent);
  font-weight: 600;
}

/* ---------- Site Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: #fff;
  box-shadow: var(--shadow);
  height: var(--header-height);
  transition: box-shadow var(--transition);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.site-logo img,
.site-logo .custom-logo,
.site-header .custom-logo-link img {
  height: 50px !important;
  width: auto !important;
  max-height: 50px !important;
  max-width: 240px !important;
  object-fit: contain;
}

.site-logo-fallback {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 1px;
}

.site-logo-fallback .sub {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 3px;
  margin-top: -4px;
}

/* ---------- Primary Navigation ---------- */
.primary-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
  justify-content: center;
}

.primary-nav > li {
  position: relative;
}
/* 含 mega-menu 的 LI 设为 static，让 mega-menu 锚到 sticky 的 .site-header
   而不是小小的 LI，得以全屏宽展开 */
.primary-nav > li.has-mega { position: static; }

.primary-nav > li > a {
  display: inline-flex;
  align-items: center;
  padding: 0 18px;
  height: var(--header-height);
  font-size: var(--fs-md);
  font-weight: 500;
  color: var(--color-text);
  position: relative;
  white-space: nowrap; /* 中文菜单项强制不换行，防止 MacBook Air 等中小屏挤压字符 */
}

.primary-nav > li > a::after {
  content: '';
  position: absolute;
  bottom: 18px;
  left: 50%;
  transform: translateX(-50%) scaleX(0);
  width: 24px;
  height: 3px;
  background: var(--color-primary);
  transition: transform var(--transition);
}

.primary-nav > li > a:hover,
.primary-nav > li.current > a,
.primary-nav > li.active > a {
  color: var(--color-primary);
}

.primary-nav > li > a:hover::after,
.primary-nav > li.current > a::after,
.primary-nav > li.active > a::after {
  transform: translateX(-50%) scaleX(1);
}

.primary-nav .has-sub > a::before {
  content: '▾';
  margin-left: 6px;
  font-size: 0.65em;
  opacity: 0.7;
}

/* 下拉菜单 */
.primary-nav .sub-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  min-width: 200px;
  background: #fff;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  padding: 8px 0;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: var(--z-dropdown);
}

.primary-nav .has-sub:hover .sub-menu {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
  visibility: visible;
}

.primary-nav .sub-menu li a {
  display: block;
  padding: 10px 20px;
  color: var(--color-text);
  font-size: var(--fs-sm);
  white-space: nowrap;
  transition: all var(--transition-fast);
}

.primary-nav .sub-menu li a:hover {
  background: var(--color-primary-lighter);
  color: var(--color-primary);
  padding-left: 24px;
}

/* 子菜单底部"查看全部"项：加分隔线 + 主色强调 */
.primary-nav .sub-menu .sub-menu-all {
  margin-top: 4px;
  padding-top: 4px;
  border-top: 1px solid var(--color-border);
}

.primary-nav .sub-menu .sub-menu-all a {
  color: var(--color-primary);
  font-weight: 500;
}

/* 项目多时（≥10 个，如 16 大行业）改用 2 列网格布局 */
.primary-nav .sub-menu.sub-menu-2col {
  min-width: 380px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 4px;
  padding: 8px 8px;
}
.primary-nav .sub-menu.sub-menu-2col li a {
  padding: 8px 12px;
  border-radius: 4px;
}
.primary-nav .sub-menu.sub-menu-2col li a:hover {
  padding-left: 12px; /* 2 列内不要 padding-left 过大避免推挤 */
  background: var(--color-primary-lighter);
}
.primary-nav .sub-menu.sub-menu-2col .sub-menu-all {
  grid-column: 1 / -1;  /* "查看全部" 横跨两列 */
  margin-top: 6px;
  padding-top: 8px;
}

/* ---------- Mega Menu（产品中心满屏大菜单） ---------- */
/* mega-menu 锚到 .site-header 底部（site-header 是 sticky）：
   - 没滚动时：top-bar 占顶部 ~32px，site-header 接在下面，mega-menu 落在 site-header 下沿
   - 滚动后：site-header 吸顶，mega-menu 跟随保持在 header 下沿
   两种情况都不会覆盖 nav link 的可点击区，给链接留 8px 缓冲 */
.primary-nav .mega-menu {
  position: absolute;
  top: 100%;  /* 与 .sub-menu 对齐：实用工具/解决方案/项目案例 都是 100% */
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  width: min(1280px, calc(100vw - 32px));
  background: #fff;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 18px 0;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: var(--z-dropdown);
}

.primary-nav .has-sub:hover > .mega-menu {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
  visibility: visible;
  transition-delay: 100ms; /* hover-intent：扫过不触发，停留 100ms 才弹 */
}
/* 移开时立即关闭（不延迟，丝滑）*/
.primary-nav .mega-menu { transition-delay: 0ms; }

.mega-menu .mega-inner {
  width: 100%;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  gap: 28px;
  align-items: stretch;
}

/* 左侧：6 个一级分类纵列 */
.mega-menu .mega-cate-type {
  flex: 0 0 320px; /* 略缩 */
  border-right: 1px solid var(--color-border);
  padding-right: 18px;
  display: flex;
  flex-direction: column;
  gap: 1px;
}

/* 行业列表 2 列网格（16 个行业避免下拉过长） */
.mega-menu .mega-industries-wrap {
  margin-top: 4px;
}
.mega-menu .mega-industries-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2px 8px;
  padding: 0;
  margin: 0;
  list-style: none;
}
.mega-menu .mega-industry a {
  padding: 7px 10px;
  font-size: 13px;
  white-space: nowrap;
}

.mega-menu .mega-cate-type li a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 12px;
  font-size: 13.5px;
  color: var(--color-text);
  border-radius: var(--radius);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.mega-menu .mega-cate-type li a:hover {
  background: var(--color-primary-lighter);
  color: var(--color-primary);
}

.mega-menu .mega-cate-type li a .arr {
  color: var(--color-text-muted);
  font-size: 16px;
  font-weight: 300;
  transition: transform var(--transition-fast);
}

.mega-menu .mega-cate-type li a:hover .arr {
  color: var(--color-primary);
  transform: translateX(3px);
}

/* 特色高亮：常规气体检测仪 */
.mega-menu .mega-cate-type li.is-featured a {
  color: var(--color-primary);
  font-weight: 600;
}

/* 查看全部产品 */
/* 左栏分组分割线（产品分类组 ←→ 行业方案组） */
.mega-menu .mega-cate-type .mega-section-divider {
  margin: 10px 4px 8px;
  height: 1px;
  background: var(--color-border);
  list-style: none;
}

/* 「按行业找方案」组首标题 — 蓝色，可点击进 /solutions/ 总览 */
.mega-menu .mega-cate-type .mega-section-title a {
  color: var(--color-primary);
  font-weight: 600;
  font-size: 14px;
  letter-spacing: 0.3px;
}
.mega-menu .mega-cate-type .mega-section-title a::after {
  display: none;
}
.mega-menu .mega-cate-type .mega-section-title a:hover {
  background: rgba(30, 75, 143, 0.06);
  color: var(--color-primary);
}

/* 行业行：跟产品分类同款排版 + 略小字号 + 紧凑 padding（9 行避免过高） */
.mega-menu .mega-cate-type .mega-industry a {
  font-size: 13.5px;
  font-weight: 500;
  padding: 7px 14px;
}
.mega-menu .mega-cate-type .mega-industry a .arr {
  font-size: 14px;
}

/* 右侧：常规气体检测仪 + 气体子类流式网格 */
.mega-menu .mega-cate-com {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.mega-menu .mega-com-head {
  padding: 2px 0 8px;
}

.mega-menu .mega-com-head .title {
  display: inline-block;
  font-size: 15px;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 2px;
}

.mega-menu .mega-com-head a.title:hover {
  color: var(--color-accent);
}

.mega-menu .mega-com-head .desc {
  display: block;
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* A-Z 字母锚点条（受逸云天启发但更进一步：123 个气体一秒跳定位） */
.mega-menu .mega-gas-az {
  display: flex; flex-wrap: wrap; gap: 1px;
  padding: 6px 0 10px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 10px;
}
.mega-menu .mega-gas-az a {
  display: inline-flex; align-items: center; justify-content: center;
  width: 24px; height: 22px;
  font-size: 12px; font-weight: 600;
  color: var(--color-primary, #1E4B8F);
  border-radius: 4px;
  text-decoration: none;
  transition: all .12s;
}
.mega-menu .mega-gas-az a:hover { background: var(--color-primary, #1E4B8F); color: #fff; }
.mega-menu .mega-gas-az a.is-empty { color: #cbd5e1; pointer-events: none; }

/* 主网格容器：6 列、紧凑文本链接、可滚动（123 个气体也装得下） */
.mega-menu .mega-gas-grid {
  max-height: 360px;
  overflow-y: auto;
  overscroll-behavior: contain; /* 滚到底/顶不带动主页面滚动 */
  padding-right: 6px;
  scroll-behavior: smooth;
}
.mega-menu .mega-gas-grid::-webkit-scrollbar { width: 6px; }
.mega-menu .mega-gas-grid::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 3px; }
.mega-menu .mega-gas-grid::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

.mega-menu .mega-gas-section {
  display: grid;
  grid-template-columns: 26px 1fr;
  gap: 6px 8px;
  padding: 4px 0;
  border-bottom: 1px dashed #f1f5f9;
}
.mega-menu .mega-gas-section:last-child { border-bottom: 0; }
.mega-menu .mega-gas-section-letter {
  font-size: 13px; font-weight: 700;
  color: var(--color-accent, #FF6B35);
  padding-top: 4px;
  position: sticky; top: 0;
}
.mega-menu .mega-gas-section-items {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 1px 6px;
}
.mega-menu .mega-com-count {
  font-size: 12px; font-weight: 500; color: #94a3b8; margin-left: 4px;
}

/* mega menu 右下角：气体因子全索引大入口 */
.mega-menu .mega-factors-cta {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 16px;
  padding: 14px 18px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light, #2c64aa) 100%);
  color: #fff;
  border-radius: var(--radius);
  transition: all var(--transition-fast);
  box-shadow: 0 4px 12px rgba(30,75,143,0.18);
}
.mega-menu .mega-factors-cta:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(30,75,143,0.28);
  color: #fff;
}
.mega-menu .mega-factors-cta .cta-icon {
  font-size: 24px;
  line-height: 1;
  flex-shrink: 0;
}
.mega-menu .mega-factors-cta .cta-body {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1;
  min-width: 0;
}
.mega-menu .mega-factors-cta .cta-body strong {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.3px;
}
.mega-menu .mega-factors-cta .cta-body .cta-sub {
  font-size: 12px;
  opacity: 0.85;
  font-weight: 400;
}
.mega-menu .mega-factors-cta .cta-arrow {
  font-size: 18px;
  transition: transform 0.2s;
  flex-shrink: 0;
}
.mega-menu .mega-factors-cta:hover .cta-arrow {
  transform: translateX(4px);
}

/* 紧凑文本链接（逸云天风格）— 无背景磁贴，每行 6 列高密度 */
.mega-menu .gas-item {
  display: block;
  padding: 4px 6px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--color-text);
  border-radius: 3px;
  transition: all .12s;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  text-decoration: none;
}
.mega-menu .gas-item:hover {
  background: rgba(30, 75, 143, 0.08);
  color: var(--color-primary, #1E4B8F);
}

/* 移动端：mega menu 退化为垂直列表（不显示右栏） */
@media (max-width: 767px) {
  .primary-nav .mega-menu {
    position: static;
    transform: none;
    width: auto;
    max-width: none;
    box-shadow: none;
    opacity: 1;
    visibility: visible;
    padding: 0;
    background: var(--color-bg-alt);
    border-radius: 0;
  }

  .mega-menu .mega-inner {
    flex-direction: column;
    gap: 0;
  }

  .mega-menu .mega-cate-type {
    flex: none;
    border-right: 0;
    padding-right: 0;
  }

  .mega-menu .mega-cate-type li a {
    padding: 10px 36px;
    border-radius: 0;
  }

  /* 移动端隐藏右侧气体网格（太拥挤，直接去常规气体检测仪分类页） */
  .mega-menu .mega-cate-com {
    display: none;
  }
}

/* ---------- Header Contact (右侧电话) ---------- */
.header-contact {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

.header-phone {
  display: flex;
  align-items: center;
  gap: 10px;
}

.header-phone .icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: var(--color-primary-lighter);
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
}

.header-phone .info {
  line-height: 1.25;
}

.header-phone .label {
  display: block;
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
}

.header-phone .number {
  display: block;
  font-size: var(--fs-lg);
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.5px;
}

/* ---------- 移动端汉堡 ---------- */
.mobile-toggle {
  display: none;
  width: 40px;
  height: 40px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
}

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: transform var(--transition), opacity var(--transition);
}

.mobile-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-toggle.open span:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Section 通用 ---------- */
.section {
  padding: 80px 0;
}

.section-sm { padding: 48px 0; }
.section-lg { padding: 120px 0; }

.section-alt { background: var(--color-bg-alt); }

.section-title {
  text-align: center;
  margin-bottom: 48px;
}

.section-title .eyebrow {
  display: inline-block;
  font-size: var(--fs-sm);
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-title h2 {
  font-size: var(--fs-4xl);
  color: var(--color-text);
  margin-bottom: 12px;
}

.section-title .subtitle {
  font-size: var(--fs-md);
  color: var(--color-text-muted);
  max-width: 680px;
  margin: 0 auto;
}

/* 标题下方装饰线 */
.section-title h2::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--color-accent);
  margin: 16px auto 0;
  border-radius: var(--radius-full);
}

/* ---------- Footer ---------- */
.site-footer {
  background: var(--color-bg-dark);
  color: rgba(255, 255, 255, 0.7);
  padding: 60px 0 0;
  font-size: var(--fs-sm);
}

.footer-cols {
  display: grid;
  grid-template-columns: 1.3fr .9fr .9fr 1fr 1.1fr;
  gap: 36px;
  padding-bottom: 48px;
}

.footer-col h4 {
  color: #fff;
  font-size: var(--fs-md);
  font-weight: 600;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border-dark);
}

.footer-col ul li {
  margin-bottom: 4px;
}

.footer-col a {
  color: rgba(255, 255, 255, 0.7);
  transition: color var(--transition-fast);
  display: inline-block;
  padding: 6px 0;
  line-height: 1.5;
  min-height: 28px;
}

.footer-col a:hover {
  color: var(--color-accent);
}

@media (max-width: 767px) {
  .footer-col ul li { margin-bottom: 2px; }
  .footer-col a {
    padding: 10px 0;
    min-height: 40px;
    line-height: 1.5;
  }
}

.footer-about p {
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.65);
  margin-bottom: 16px;
}

.footer-logo {
  margin-bottom: 18px;
}

/* 上传的深色底版 Logo —— 不滤镜，保持原色 */
.footer-logo--image img {
  height: 44px;
  width: auto;
  max-width: 220px;
  display: block;
  opacity: 0.95;
}

/* 默认：CSS 排版的品牌文字（深色底上锐利、不依赖图片资源） */
.footer-logo--text {
  display: inline-flex;
  align-items: baseline;
  gap: 12px;
  line-height: 1;
  user-select: none;
}
.footer-logo--text .brand-cn {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 4px;
  color: #fff;
}
.footer-logo--text .brand-en {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 2px;
  color: rgba(255, 255, 255, 0.6);
  position: relative;
  top: -2px;
}
.footer-logo--text .brand-en sup {
  font-size: 9px;
  margin-left: 1px;
  vertical-align: super;
  color: var(--color-accent);
}

.footer-tagline {
  color: #fff !important;
  font-weight: 500;
  margin-top: 4px;
  letter-spacing: .03em;
}

.footer-contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
  color: rgba(255, 255, 255, 0.8);
}

.footer-contact-item .icon {
  flex-shrink: 0;
  width: 20px;
  margin-top: 2px;
  color: var(--color-accent);
}

.footer-qrcode {
  display: flex;
  gap: 16px;
  margin-top: 20px;
}

.footer-qrcode .qr-item {
  text-align: center;
  font-size: var(--fs-xs);
}

.footer-qrcode .qr-img {
  width: 96px;
  height: 96px;
  background: #fff;
  border-radius: var(--radius);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: var(--fs-xs);
}

.footer-bottom {
  border-top: 1px solid var(--color-border-dark);
  padding: 20px 0;
  text-align: center;
  color: rgba(255, 255, 255, 0.5);
  font-size: var(--fs-xs);
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.6);
  display: inline-block;
  padding: 10px 6px;
  line-height: 1.6;
  min-height: 40px;
}

/* ---------- 响应式：MacBook Air / 小笔记本 (1200-1440px) ---------- */
@media (max-width: 1440px) and (min-width: 1200px) {
  .primary-nav > li > a { padding: 0 12px; font-size: 14px; }
  .primary-nav { gap: 0; }
}

/* ---------- 响应式：iPad 横屏 / 小窗口（992-1199px）：保留完整导航 + 隐藏次要元素让导航有空间 ---------- */
@media (max-width: 1199px) and (min-width: 992px) {
  .top-bar { display: none; } /* 隐藏顶部欢迎条，省 32px 高度 */
  .header-contact { display: none; } /* 隐藏右侧电话块，省 ~180px 给导航 */
  .primary-nav > li > a { padding: 0 10px; font-size: 13.5px; }
  .header-search { max-width: 200px; } /* 搜索框缩窄 */
}

/* ---------- 响应式：iPad 竖屏 / 小平板 (768-991px)：切换为汉堡抽屉菜单 ---------- */
@media (max-width: 991px) and (min-width: 768px) {
  .top-bar { display: none; }
  .mobile-toggle { display: flex; }
  .header-contact { display: none; }
  .header-search { display: none; } /* 搜索移入汉堡抽屉里再考虑 */

  /* 抽屉模式 */
  .primary-nav {
    position: fixed;
    top: var(--header-height);
    right: -100%;
    width: 50%;
    max-width: 380px;
    height: calc(100vh - var(--header-height));
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start; /* 顶端起，避免内容被挤出可视区 */
    padding: 20px 0;
    transition: right .25s ease;
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
    overflow-y: auto;
    overscroll-behavior: contain;
    z-index: 100;
    gap: 0;
  }
  .primary-nav.open { right: 0; }
  .primary-nav > li > a {
    display: flex;
    width: 100%;
    padding: 14px 24px;
    height: auto;
    border-bottom: 1px solid var(--color-border);
    justify-content: space-between;
    align-items: center;
    white-space: nowrap;
  }
  /* 隐藏桌面下划线指示器 */
  .primary-nav > li > a::after {
    content: '';
    position: static;
    transform: none;
    width: auto;
    height: auto;
    background: none;
  }
  .primary-nav .has-sub > a::before { display: none; }
  .primary-nav > li.has-sub > a::after {
    content: '▾';
    color: var(--color-text-muted);
    font-size: 14px;
    margin-left: auto;
    transition: transform .25s ease;
  }
  .primary-nav > li.has-sub.expanded > a::after {
    transform: rotate(180deg);
    color: var(--color-primary);
  }
  /* sub-menu / mega-menu 抽屉手风琴 */
  .primary-nav .sub-menu,
  .primary-nav .mega-menu,
  .primary-nav .has-sub:hover .sub-menu,
  .primary-nav .has-sub:hover .mega-menu,
  .primary-nav .has-sub.expanded .sub-menu,
  .primary-nav .has-sub.expanded .mega-menu {
    position: static;
    transform: none;
    box-shadow: none;
    padding: 0;
    background: var(--color-bg-alt);
    min-width: 0;
    display: none;
    opacity: 1;
    visibility: visible;
    width: 100%;
  }
  .primary-nav .has-sub.expanded > .sub-menu,
  .primary-nav .has-sub.expanded > .mega-menu {
    display: block;
  }
  .primary-nav .sub-menu li a { padding: 10px 36px; }
}

/* ---------- 响应式：平板 ---------- */
@media (max-width: 1199px) {
  .container { padding: 0 16px; } /* 移动端缩小到 16px 多挤一点空间 */
  .primary-nav > li > a { padding: 0 14px; }
  .section { padding: 64px 0; }
  .footer-cols {
    grid-template-columns: 1fr 1fr;
    gap: 36px;
  }
}

/* ---------- 响应式：移动端 ---------- */
@media (max-width: 767px) {
  .site-header {
    height: var(--header-height-mobile);
  }

  .top-bar {
    display: none;
  }

  .mobile-toggle {
    display: flex;
  }

  .site-logo img {
    height: 36px;
  }

  .site-logo-fallback {
    font-size: 1.25rem;
  }

  .header-contact {
    display: none;
  }

  /* 移动菜单抽屉 */
  .primary-nav {
    position: fixed;
    top: var(--header-height-mobile);
    right: -100%;
    width: 80%;
    max-width: 320px;
    height: calc(100vh - var(--header-height-mobile));
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start; /* 顶端起，超出滚动；不再继承桌面 center 导致内容被挤出可视区 */
    padding: 20px 0;
    transition: right var(--transition);
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.1);
    overflow-y: auto;
    overscroll-behavior: contain; /* 抽屉滚动不带动主页 */
  }

  .primary-nav.open {
    right: 0;
  }

  .primary-nav > li > a {
    display: flex;
    width: 100%;
    padding: 14px 24px;
    height: auto;
    border-bottom: 1px solid var(--color-border);
    justify-content: space-between;
    align-items: center;
  }

  /* 桌面端的 ▾ 内联文字（::before）在移动端隐藏，避免和右侧箭头重复 */
  .primary-nav .has-sub > a::before {
    display: none;
  }

  /* 移动端用 ::after 当右侧展开箭头（覆盖桌面 absolute 下划线） */
  .primary-nav > li > a::after {
    content: '';
    position: static;
    transform: none;
    width: auto;
    height: auto;
    background: none;
  }
  .primary-nav > li.has-sub > a::after {
    content: '▾';
    color: var(--color-text-muted);
    font-size: 14px;
    margin-left: auto;
    transition: transform 0.25s ease;
  }
  .primary-nav > li.has-sub.expanded > a::after {
    transform: rotate(180deg);
    color: var(--color-primary);
  }

  /* 子菜单和 mega-menu 移动端只看 .expanded 类，完全不响应 :hover（避免触摸残留导致闪烁）
     用 :where() 包 :hover 选择器，特异性归零，被 .expanded 规则正常覆盖 */
  .primary-nav .sub-menu,
  .primary-nav .mega-menu,
  .primary-nav :where(.has-sub:hover) .sub-menu,
  .primary-nav :where(.has-sub:hover) .mega-menu {
    position: static;
    transform: none !important;
    box-shadow: none;
    padding: 0;
    background: var(--color-bg-alt);
    min-width: 0;
    display: none !important;
    opacity: 1;
    visibility: visible;
    width: 100%;
  }
  .primary-nav .has-sub.expanded > .sub-menu,
  .primary-nav .has-sub.expanded > .mega-menu {
    display: block !important;
  }

  .primary-nav .sub-menu li a {
    padding: 10px 36px;
  }


  .section {
    padding: 48px 0;
  }

  .section-title { margin-bottom: 32px; }
  .section-title h2 { font-size: var(--fs-2xl); }

  .footer-cols {
    grid-template-columns: 1fr;
    gap: 32px;
    padding-bottom: 32px;
  }

  /* 底部固定电话条（移动端特有） */
  .mobile-bottom-bar {
    display: flex;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--color-primary);
    z-index: var(--z-floating);
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.15);
  }

  .mobile-bottom-bar a {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 10px;
    color: #fff;
    font-size: var(--fs-xs);
    border-right: 1px solid rgba(255, 255, 255, 0.15);
  }

  .mobile-bottom-bar a:last-child {
    border-right: none;
  }

  .mobile-bottom-bar a.primary {
    background: var(--color-accent);
  }

  .mobile-bottom-bar .icon {
    font-size: 18px;
    margin-bottom: 2px;
  }

  /* 为底部固定条腾空间 */
  body {
    padding-bottom: 56px;
  }
}

@media (min-width: 768px) {
  .mobile-bottom-bar {
    display: none;
  }
}