/* ===== CSS Variables ===== */
:root {
  --primary: #1a5276;
  --primary-light: #2980b9;
  --accent: #e67e22;
  --accent-light: #f39c12;
  --bg: #f8f9fa;
  --surface: #ffffff;
  --text: #2c3e50;
  --text-muted: #6c757d;
  --border: #dee2e6;
  --max-width: 1200px;
  --header-h: 60px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,.06);
  --shadow-hover: 0 4px 16px rgba(0,0,0,.1);
}

/* ===== Reset ===== */
*, ::before, ::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--accent); }
ul { list-style: none; }

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 16px;
}

/* ===== Header ===== */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
}
.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  flex-shrink: 0;
}
.logo-img {
  width: auto;
  height: 40px;
  display: block;
}
.logo-tagline {
  font-size: 14px;
  font-weight: 600;
  color: var(--primary);
  white-space: nowrap;
  padding-left: 12px;
  border-left: 1px solid var(--border);
  line-height: 1.2;
}
/* 窄屏隐藏广告语 */
@media (max-width: 480px) {
  .logo-tagline { display: none; }
}

/* Hamburger */
.menu-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  z-index: 101;
}
.menu-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all .3s;
}
.menu-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.main-nav {
  display: none;
  position: absolute;
  top: var(--header-h);
  left: 0;
  right: 0;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-direction: column;
  padding: 8px 0;
  box-shadow: var(--shadow);
}
.main-nav.open { display: flex; }
.nav-link {
  padding: 12px 20px;
  font-size: 15px;
  color: var(--text);
  border-left: 3px solid transparent;
}
.nav-link:hover, .nav-link.active {
  color: var(--primary);
  background: #f0f4f8;
  border-left-color: var(--primary);
}

/* ===== Main Content ===== */
.main-content { min-height: calc(100vh - var(--header-h) - 200px); }
.section { padding: 32px 0; }
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 20px;
}
.section-head h2 { font-size: 22px; font-weight: 600; }
.more-link { font-size: 14px; }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #2c6b9c 100%);
  color: #fff;
  text-align: center;
  padding: 48px 16px;
}
.hero-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
}
.hero-subtitle {
  font-size: 16px;
  opacity: .85;
}

/* ===== Section Description ===== */
.section-desc {
  font-size: 14px;
  color: var(--text-muted);
  margin-top: -12px;
  margin-bottom: 20px;
}

/* ===== Category Blocks (Homepage) ===== */
.category-block {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 32px;
  border: 1px solid var(--border);
  transition: box-shadow .3s;
}
.category-block:hover {
  box-shadow: var(--shadow-hover);
}
.category-block-img {
  overflow: hidden;
  background: #eaf2f8;
}
.category-block-img img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  transition: transform .4s;
}
.category-block:hover .category-block-img img {
  transform: scale(1.05);
}
.category-block-text {
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.category-block-text h3 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 8px;
}
.category-block-text h3 a {
  color: var(--primary);
}
.category-block-text h3 a:hover {
  color: var(--accent);
}
.category-block-desc {
  font-size: 15px;
  color: var(--text);
  font-weight: 500;
  margin-bottom: 8px;
}
.category-block-summary {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 16px;
}
.category-block-btn {
  display: inline-block;
  padding: 8px 20px;
  background: var(--primary);
  color: #fff;
  border-radius: var(--radius);
  font-size: 14px;
  align-self: flex-start;
  transition: background .2s;
}
.category-block-btn:hover {
  background: var(--primary-light);
  color: #fff;
}

/* ===== Product Grid ===== */
.product-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}
.product-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color .2s, transform .2s;
}
.product-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
}
.product-card a { color: inherit; display: block; }
.product-img {
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #f0f0f0;
}
.product-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.product-info { padding: 16px; }
.product-info h3 { font-size: 16px; font-weight: 600; margin-bottom: 6px; }
.product-cat {
  font-size: 12px;
  padding: 2px 8px;
  background: #eaf2f8;
  color: var(--primary);
  border-radius: 999px;
  display: inline-block;
  margin-bottom: 4px;
}
.product-price {
  font-size: 15px;
  font-weight: 600;
  color: var(--accent);
  margin: 4px 0;
}
.product-desc {
  font-size: 13px;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ===== Page Header ===== */
.page-header {
  background: linear-gradient(135deg, var(--primary) 0%, #2c6b9c 100%);
  color: #fff;
  padding: 36px 0;
  text-align: center;
}
.page-header h1 { font-size: 24px; font-weight: 700; }
.page-desc { font-size: 14px; opacity: .85; margin-top: 4px; }

/* ===== Filter Bar ===== */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 20px;
  padding: 12px 0;
}
.filter-label { font-size: 14px; color: var(--text-muted); }
.filter-btn {
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 13px;
  color: var(--text);
  background: var(--surface);
}
.filter-btn:hover, .filter-btn.active {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  padding: 12px 0;
  font-size: 13px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.breadcrumb .sep { margin: 0 8px; color: var(--text-muted); }
.breadcrumb .current { color: var(--text-muted); }

/* ===== Product Detail ===== */
.product-detail { padding: 24px 0 48px; }
.product-detail-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  margin-bottom: 32px;
}
.product-main-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: #f0f0f0;
  aspect-ratio: 4 / 3;
}
.product-main-img img { width: 100%; height: 100%; object-fit: cover; }
.product-main-img.placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 14px;
}
.product-title { font-size: 24px; font-weight: 700; margin-bottom: 12px; }
.product-tag {
  font-size: 12px;
  padding: 3px 10px;
  background: #eaf2f8;
  color: var(--primary);
  border-radius: 999px;
  display: inline-block;
  margin-bottom: 8px;
}
.product-price-lg {
  font-size: 22px;
  font-weight: 700;
  color: var(--accent);
  margin: 12px 0;
}
.product-desc-lg {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 16px;
}
.product-features { margin: 16px 0; }
.product-features h3 { font-size: 16px; font-weight: 600; margin-bottom: 10px; }
.features-list li {
  padding: 6px 0 6px 20px;
  position: relative;
  font-size: 14px;
}
.features-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 12px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

/* ===== Contact Card (右侧面板) ===== */
.product-contact-card {
  margin-top: 16px;
  padding: 12px 14px;
  background: #fff8e1;
  border: 1px solid #ffe082;
  border-radius: var(--radius);
}
.contact-card-inner {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
}
.contact-icon { font-size: 18px; }
.contact-text { color: var(--text); }
.contact-text strong { color: #e67e22; }

/* ===== Image Watermark ===== */
.product-main-img {
  position: relative;
}
.img-watermark {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 6px 12px;
  background: rgba(0,0,0,.55);
  color: rgba(255,255,255,.85);
  font-size: 12px;
  text-align: center;
  pointer-events: none;
  user-select: none;
}

/* ===== Contact Row in Table ===== */
.contact-row {
  background: #fff8e1 !important;
}
.contact-row .param-value strong {
  color: #e67e22;
}

/* ===== Related Models Table ===== */
.related-models-wrap {
  margin: 16px 0;
  overflow-x: auto;
}
.related-table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 14px;
}
.related-table th {
  background: var(--primary);
  color: #fff;
  padding: 7px 14px;
  text-align: left;
  font-weight: 600;
}
.related-table th:first-child { width: 180px; }
.related-table td {
  padding: 7px 14px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
.related-table th[align="center"],
.related-table td[align="center"],
.related-table th[align="right"],
.related-table td[align="right"] {
  text-align: left;
}
.related-table tbody tr:nth-child(even) td {
  background: #f8f9fa;
}
.related-table tbody tr:hover td {
  background: #eaf2f8;
}
.related-table .model-code {
  font-weight: 700;
  color: var(--primary);
  font-family: "Courier New", monospace;
  white-space: nowrap;
}
.related-table .model-info {
  color: var(--text);
}
.product-contact-footer {
  margin-top: 32px;
  padding: 16px 20px;
  background: #f8f9fa;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-align: center;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text);
}
.product-contact-footer strong {
  color: var(--primary);
}
.product-body {
  font-size: 15px;
  line-height: 1.8;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.product-body h2 { font-size: 20px; font-weight: 600; margin: 32px 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--primary); }
/* 知识文章：只保留最顶（第一个 h2）和最底（最后一个 h2）标题下横线，中间章节标题不加横线 */
.article-body h2:not(:first-of-type):not(:last-of-type) { border-bottom: none; padding-bottom: 0; }
.product-body h3 { font-size: 17px; font-weight: 600; margin: 20px 0 10px; color: var(--primary); }
.product-body p { margin-bottom: 12px; }
.product-body ul, .product-body ol { margin: 0 0 16px 20px; }
.product-body li { margin-bottom: 6px; line-height: 1.7; }
.product-body img { border-radius: var(--radius); margin: 12px 0; }
.product-body strong { color: var(--primary); }

/* ===== Knowledge List ===== */
.knowledge-list {
  margin: 20px 0;
}
.knowledge-items {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.knowledge-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  transition: background .15s;
}
.knowledge-item:last-child {
  border-bottom: none;
}
.knowledge-item:hover {
  background: #f0f4f8;
}
.knowledge-letter-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  flex-shrink: 0;
}
/* 知识列表三列表格：序号 / 标题 / 发布日期 */
.knowledge-item .k-no {
  width: 56px;
  flex-shrink: 0;
  font-size: 14px;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}
.knowledge-item .k-title {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.knowledge-item .k-date {
  width: 96px;
  flex-shrink: 0;
  text-align: right;
  font-size: 13px;
  color: var(--text-muted);
}
.knowledge-head {
  background: #f5f7fa;
  font-weight: 700;
  font-size: 13px;
  color: var(--text-muted);
  cursor: default;
}
.knowledge-head:hover { background: #f5f7fa; }
.knowledge-head .k-no { font-weight: 700; }
.knowledge-head .k-date { font-weight: 700; }
.knowledge-title {
  font-size: 15px;
  color: var(--text);
  text-decoration: none;
  line-height: 1.5;
}
.knowledge-title:hover {
  color: var(--primary);
  text-decoration: underline;
}

/* 正文中的表格 */
.product-body-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0 20px;
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.product-body-content table th {
  background: var(--primary);
  color: #fff;
  padding: 7px 12px;
  text-align: left;
  font-weight: 600;
}
.product-body-content table td {
  padding: 7px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
/* 覆盖 markdown 中的 align="center" */
.product-body-content table th[align="center"],
.product-body-content table td[align="center"] {
  text-align: left;
}
.product-body-content table th[align="right"],
.product-body-content table td[align="right"] {
  text-align: left;
}
.product-body-content table tbody tr:nth-child(even) td {
  background: #f8f9fa;
}
.product-body-content table tbody tr:hover td {
  background: #eaf2f8;
}

/* 安装与使用中的步骤列表 */
.product-body-content ol {
  counter-reset: step;
  list-style: none;
  padding: 0;
}
.product-body-content ol > li {
  counter-increment: step;
  padding: 8px 12px 8px 36px;
  position: relative;
  background: #f8f9fa;
  margin-bottom: 6px;
  border-radius: var(--radius);
  border-left: 3px solid var(--primary);
}
.product-body-content ol > li::before {
  content: counter(step);
  position: absolute;
  left: 10px;
  top: 8px;
  width: 20px;
  height: 20px;
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  text-align: center;
  line-height: 20px;
  border-radius: 50%;
}
/* 嵌套在步骤里的子列表 */
.product-body-content ol > li > ul,
.product-body-content ol > li > p + ul {
  margin-top: 10px;
  margin-left: 0;
  padding: 10px 14px 10px 20px;
  background: #ffffff;
  border-radius: 6px;
  border-left: 2px dashed var(--primary-light);
  list-style: none;
}
.product-body-content ol > li > ul li {
  background: transparent;
  border: none;
  padding: 4px 0 4px 16px;
  margin-bottom: 4px;
  font-size: 14px;
  position: relative;
  list-style: none;
  border-radius: 0;
}
.product-body-content ol > li > ul li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: var(--primary);
  font-weight: 700;
  font-size: 18px;
  line-height: 1;
}

/* 注意事项/提示块 */
.product-body-content p strong:only-child {
  display: block;
  margin-top: 12px;
}

/* 列表项中的次要文字缩进 */
.product-body-content ul {
  list-style: disc;
  padding-left: 20px;
}
.product-body-content ul li {
  padding: 2px 0;
}

/* ===== Product Nav ===== */
.product-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 24px;
}
.product-nav-btn {
  flex: 1;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-align: center;
  color: var(--text);
}
.product-nav-btn:hover { border-color: var(--primary); }
.nav-label { font-size: 12px; color: var(--text-muted); display: block; }
.nav-title { font-size: 14px; font-weight: 500; display: block; margin-top: 2px; max-width: 200px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.product-nav-btn.next { text-align: right; }

.back-link {
  text-align: center;
  margin-top: 24px;
}
.back-link a { font-size: 14px; }

/* ===== Pagination ===== */
.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-top: 32px;
  padding: 20px 0;
}
.page-btn {
  padding: 8px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 14px;
  color: var(--text);
  background: var(--surface);
}
.page-btn:hover { border-color: var(--primary); }
.page-info { font-size: 14px; color: var(--text-muted); }
/* 页码跳转框（知识列表页） */
.jump-box { display: inline-flex; align-items: center; gap: 8px; margin-left: 8px; }
.jump-input {
  width: 64px; padding: 7px 8px; border: 1px solid var(--border);
  border-radius: var(--radius); font-size: 14px; color: var(--text);
  background: var(--surface);
}
.jump-input:focus { outline: none; border-color: var(--primary); }
.jump-btn { padding: 8px 14px; cursor: pointer; border: 1px solid var(--border); }
/* 顶部翻页（列表页首字母搜索下方） */
.pagination-top {
  margin-top: 0;
  padding: 16px 0;
  margin-bottom: 8px;
}
.empty-state { text-align: center; padding: 60px 0; color: var(--text-muted); }

/* ===== Back to Top ===== */
#back-to-top {
  position: fixed;
  bottom: 80px;
  right: 30px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .3s, transform .3s;
  z-index: 999;
  box-shadow: 0 2px 8px rgba(0,0,0,.2);
}
#back-to-top.show {
  opacity: 1;
  transform: translateY(0);
}
#back-to-top:hover {
  background: var(--primary-light);
}

/* ===== Letter Search ===== */
/* 知识搜索框（方案B，替代首字母搜索） */
.knowledge-search {
  display: flex;
  gap: 10px;
  margin-bottom: 24px;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}
.knowledge-search input {
  flex: 1;
  height: 42px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 15px;
  color: var(--text);
  background: var(--surface);
  outline: none;
}
.knowledge-search input:focus {
  border-color: var(--primary);
}
.knowledge-search .search-btn {
  height: 42px;
  padding: 0 24px;
  border: 1px solid var(--primary);
  border-radius: var(--radius);
  background: var(--primary);
  color: #fff;
  font-size: 15px;
  cursor: pointer;
  white-space: nowrap;
}
.knowledge-search .search-btn:hover {
  opacity: .9;
}
/* 搜索结果容器与原文列表共用 knowledge-items 样式 */
.knowledge-items .letter-empty {
  text-align: center;
  padding: 30px 0;
  color: var(--text-muted);
}
@media (max-width: 480px) {
  .knowledge-search {
    flex-direction: column;
  }
  .knowledge-search .search-btn {
    width: 100%;
  }
}
.letter-search {
  margin-bottom: 24px;
  padding: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}
.letter-label {
  display: block;
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 10px;
  font-weight: 500;
}
.letter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}
.letter-btn {
  width: 34px;
  height: 34px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all .2s;
}
.letter-btn.disabled {
  opacity: .35;
  cursor: not-allowed;
  color: var(--text-muted);
  border-color: var(--border);
  background: transparent;
}
.letter-btn.disabled:hover {
  border-color: var(--border);
  color: var(--text-muted);
  background: transparent;
}
.letter-empty {
  padding: 32px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}
.letter-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: #eaf2f8;
}
.letter-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}
.letter-btn.active:hover {
  background: var(--primary-light);
}

/* ===== Parameter Table ===== */
.param-table-wrap {
  overflow-x: auto;
  margin: 16px 0;
}
.param-table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.param-table tr {
  border-bottom: 1px solid var(--border);
}
.param-table tr:nth-child(even) {
  background: #f8f9fa;
}
.param-table tr:last-child {
  border-bottom: none;
}
.param-name {
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  background: #f0f4f8;
  width: 35%;
  border-right: 1px solid var(--border);
}
.param-value {
  padding: 10px 16px;
  font-size: 14px;
  color: var(--text);
}

/* ===== Model Description ===== */
.model-desc {
  margin: 16px 0;
  padding: 20px;
  background: #f8f9fa;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 14px;
  line-height: 1.9;
}
.model-desc table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 13px;
}
.model-desc table th {
  background: var(--primary);
  color: #fff;
  padding: 8px 12px;
  text-align: left;
  font-weight: 600;
}
.model-desc table th:first-child { border-radius: 6px 0 0 0; }
.model-desc table th:last-child { border-radius: 0 6px 0 0; }
.model-desc table td {
  padding: 6px 12px;
  border-bottom: 1px solid var(--border);
}
.model-desc table tr:nth-child(even) td {
  background: #f0f4f8;
}
.model-desc table tr:hover td {
  background: #eaf2f8;
}
.model-desc p {
  margin-bottom: 8px;
}
.model-desc strong {
  color: var(--primary);
}
.model-desc code {
  background: #eaf2f8;
  padding: 1px 6px;
  border-radius: 3px;
  font-size: 13px;
  color: #c0392b;
}
}
.model-info {
  font-size: 14px;
  color: var(--text-muted);
  flex: 1;
}
.site-footer {
  background: var(--primary);
  color: rgba(255,255,255,.85);
  padding: 0;
  margin-top: 48px;
}
.footer-inner { padding: 32px 16px 16px; }
.footer-brand { font-size: 18px; font-weight: 700; margin-bottom: 4px; }
.footer-desc { font-size: 13px; opacity: .7; margin-bottom: 16px; }
.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 20px;
}
.footer-link { color: rgba(255,255,255,.7); font-size: 13px; }
.footer-link:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.15);
  padding-top: 16px;
  font-size: 12px;
  opacity: .6;
  text-align: center;
}
.footer-bottom .footer-brand-link {
  color: inherit;
  text-decoration: none;
}
.footer-bottom .footer-brand-link:hover {
  color: #fff;
  text-decoration: underline;
}
.footer-bottom .footer-sitemap-link {
  color: inherit;
  text-decoration: none;
}
.footer-bottom .footer-sitemap-link:hover {
  color: #fff;
  text-decoration: underline;
}
.footer-bottom .footer-icp-link {
  color: inherit;
  text-decoration: none;
}
.footer-bottom .footer-icp-link:hover {
  color: #fff;
  text-decoration: underline;
}
.footer-bottom .footer-beian-icon {
  display: inline-block;
  height: 14px;
  width: auto;
  vertical-align: middle;
  margin: 0 4px;
}
.footer-bottom .footer-police-link {
  color: inherit;
  text-decoration: none;
}
.footer-bottom .footer-police-link:hover {
  color: #fff;
  text-decoration: underline;
}

/* =============================================
   Desktop ≥ 768px
   ============================================= */
@media (min-width: 768px) {
  body { font-size: 16px; }
  .container { padding: 0 24px; }

  .menu-toggle { display: none; }
  .main-nav {
    display: flex !important;
    position: static;
    flex-direction: row;
    border: none;
    background: none;
    box-shadow: none;
    padding: 0;
    gap: 4px;
  }
  .nav-link {
    padding: 8px 16px;
    border: none;
    border-radius: var(--radius);
    font-size: 14px;
  }
  .nav-link:hover, .nav-link.active {
    background: #eaf2f8;
    color: var(--primary);
    border: none;
  }

  .hero { padding: 64px 24px; }
  .hero-title { font-size: 36px; }
  .hero-subtitle { font-size: 18px; }

  .section { padding: 40px 0; }

  .category-card { padding: 24px 32px; }
  .category-card h3 { font-size: 18px; }

  /* ===== Category Block (Desktop) ===== */
  .category-block {
    flex-direction: row;
    margin-bottom: 40px;
  }
  .category-block.reverse {
    flex-direction: row-reverse;
  }
  .category-block-img {
    flex: 0 0 40%;
  }
  .category-block-img img {
    height: 100%;
    min-height: 280px;
  }
  .category-block-text {
    flex: 1;
    padding: 32px 36px;
  }
  .category-block-text h3 {
    font-size: 26px;
  }
  .category-block-summary {
    font-size: 15px;
  }

  .letter-bar {
    gap: 6px;
  }
  .letter-btn {
    width: 40px;
    height: 40px;
    font-size: 15px;
  }

  .product-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }

  .page-header { padding: 48px 0; }
  .page-header h1 { font-size: 28px; }

  .product-detail-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }
  .product-title { font-size: 28px; }

  .footer-nav { gap: 24px; }
}

/* Desktop ≥ 1024px */
@media (min-width: 1024px) {
  .product-grid { grid-template-columns: repeat(3, 1fr); gap: 24px; }

  .hero { padding: 80px 24px; }
  .hero-title { font-size: 42px; }

  .product-detail { padding: 32px 0 64px; }
  .product-main-img { aspect-ratio: 3 / 2; }
}