/* ==========================================================================
   寰宇云 (Huanyu Cloud) - 全球坐标系统设计规范样式表
   版本：2026 纯白科技 / 极简坐标规范
   ========================================================================== */

:root {
  /* 调色盘规范 */
  --bg-main: #F7F9FB;
  --bg-white: #FFFFFF;
  --bg-secondary: #F1F5F7;
  --text-primary: #17232D;
  --text-body: #52606A;
  --text-secondary: #83909A;
  --coord-blue: #2D6FD2;
  --node-cyan: #2E8E86;
  --accent-orange: #D98A4F;
  --light-blue: #EDF4FC;
  --light-cyan: #EDF7F5;
  --border-color: #DDE5EA;
  --footer-bg: #EEF3F6;
  --footer-text: #41505A;

  /* 字体规范 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  
  /* 尺寸 */
  --max-width: 1200px;
  --article-width: 800px;
  --header-height: 70px;
  --transition-fast: 0.2s ease;
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-family: var(--font-sans);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-main);
  color: var(--text-body);
  font-size: 1.0625rem; /* 17px */
  line-height: 1.75;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* 链接与排版 */
a {
  color: var(--coord-blue);
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

a:hover {
  color: #1b52a4;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(2.25rem, 4vw, 3.25rem); /* 36px ~ 52px */
}

h2 {
  font-size: clamp(1.65rem, 2.5vw, 2.125rem); /* 26px ~ 34px */
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.35rem; /* 21.6px */
  margin-bottom: 0.5rem;
}

p {
  margin-bottom: 1.25rem;
}

p:last-child {
  margin-bottom: 0;
}

ul, ol {
  padding-left: 1.4rem;
  margin-bottom: 1.25rem;
}

li {
  margin-bottom: 0.5rem;
}

/* 容器与网格辅助 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* 按钮规范 */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background-color: var(--coord-blue);
  color: #FFFFFF;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.75rem 1.6rem;
  border-radius: 4px;
  border: 1px solid var(--coord-blue);
  cursor: pointer;
  white-space: nowrap;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.btn-primary:hover {
  background-color: #2159b3;
  color: #FFFFFF;
  transform: translateY(-1px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background-color: var(--bg-white);
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.75rem 1.6rem;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  cursor: pointer;
  white-space: nowrap;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.btn-secondary:hover {
  background-color: var(--bg-secondary);
  border-color: #cbd5dc;
  color: var(--text-primary);
}

.btn-subtle {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--coord-blue);
  padding: 0.4rem 0.6rem;
  border-radius: 4px;
  background-color: var(--light-blue);
}

.btn-subtle:hover {
  background-color: #dbe9f9;
  color: #1b52a4;
}

/* ==========================================================================
   Header (顶部导航)
   ========================================================================== */
.site-header {
  height: var(--header-height);
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
}

.logo-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.brand-text-wrap {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--text-secondary);
  line-height: 1.1;
  margin-top: 2px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 1.4rem;
}

.nav-link {
  font-size: 0.925rem;
  font-weight: 500;
  color: var(--text-body);
  position: relative;
  padding: 0.5rem 0.2rem;
}

.nav-link:hover {
  color: var(--coord-blue);
}

.nav-link.active {
  color: var(--coord-blue);
  font-weight: 600;
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--coord-blue);
  border-radius: 1px;
}

.header-action {
  display: flex;
  align-items: center;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border-color);
  padding: 0.45rem 0.75rem;
  font-size: 0.9rem;
  color: var(--text-primary);
  border-radius: 4px;
  cursor: pointer;
  align-items: center;
  gap: 0.4rem;
}

/* 移动端菜单抽屉 */
.mobile-nav-panel {
  display: none;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  padding: 1.25rem 1.5rem 1.75rem;
}

.mobile-nav-panel.open {
  display: block;
}

.mobile-nav-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.mobile-nav-item {
  border-bottom: 1px solid #f1f5f7;
  padding: 0.8rem 0;
}

.mobile-nav-item a {
  display: block;
  font-size: 1.05rem;
  color: var(--text-primary);
  font-weight: 500;
}

.mobile-nav-cta {
  margin-top: 1.25rem;
}

/* ==========================================================================
   Hero 全球坐标系统
   ========================================================================== */
.hero-section {
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  padding: 3.5rem 0 3rem;
  position: relative;
  overflow: hidden;
  /* 极细坐标网格背景 */
  background-image: 
    linear-gradient(to right, rgba(221, 229, 234, 0.45) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(221, 229, 234, 0.45) 1px, transparent 1px);
  background-size: 40px 40px;
  background-position: center top;
}

.hero-content {
  max-width: 900px;
  margin: 0 auto 2.5rem;
  text-align: center;
  position: relative;
  z-index: 2;
}

.hero-tag-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background-color: var(--light-blue);
  color: var(--coord-blue);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.35rem 0.9rem;
  border-radius: 20px;
  border: 1px solid #d4e3f8;
  margin-bottom: 1.25rem;
}

.hero-tag-badge .coord-dot {
  width: 6px;
  height: 6px;
  background-color: var(--node-cyan);
  border-radius: 50%;
  display: inline-block;
}

.hero-slogan {
  font-size: clamp(1.85rem, 3.5vw, 2.75rem);
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--coord-blue);
  font-weight: 600;
  margin-bottom: 1.25rem;
  letter-spacing: 0.02em;
}

.hero-h1-seo {
  font-size: 1.25rem;
  color: var(--text-primary);
  font-weight: 700;
  margin-bottom: 1rem;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--text-body);
  max-width: 780px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Hero 网络坐标导航系统 (XY 坐标抽象) */
.hero-coord-nav {
  margin-top: 2.5rem;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  box-shadow: 0 4px 20px rgba(23, 35, 45, 0.04);
  position: relative;
  z-index: 2;
  overflow: hidden;
}

.coord-nav-header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 600;
}

.coord-nav-axis-indicator {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.coord-axis-tag {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.coord-axis-tag span {
  color: var(--coord-blue);
  font-weight: 700;
}

.coord-nav-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  divide-x: 1px solid var(--border-color);
}

.coord-cell {
  padding: 1.5rem 1.25rem;
  border-right: 1px solid var(--border-color);
  position: relative;
  transition: background-color var(--transition-fast);
}

.coord-cell:last-child {
  border-right: none;
}

.coord-cell:hover {
  background-color: var(--light-blue);
}

.coord-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.6rem;
}

.coord-number {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--coord-blue);
  background-color: #EDF4FC;
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  letter-spacing: 0.05em;
}

.coord-status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--node-cyan);
}

.coord-cell h3 {
  font-size: 1.15rem;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.coord-cell p {
  font-size: 0.9rem;
  color: var(--text-body);
  line-height: 1.5;
  margin-bottom: 0.85rem;
}

.coord-cell .coord-link {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--coord-blue);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.coord-cell .coord-link:hover {
  text-decoration: underline;
}

/* ==========================================================================
   模块通用样式 (Section Layout)
   ========================================================================== */
.section {
  padding: 4.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

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

.section-header {
  margin-bottom: 2.25rem;
}

.section-index {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--coord-blue);
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
}

.section-index::after {
  content: "";
  display: inline-block;
  width: 24px;
  height: 1px;
  background-color: var(--coord-blue);
}

.geo-answer {
  background-color: var(--bg-white);
  border-left: 3px solid var(--coord-blue);
  border-top: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 1.1rem 1.4rem;
  border-radius: 0 4px 4px 0;
  margin-bottom: 2rem;
  font-size: 1.05rem;
  color: var(--text-primary);
  line-height: 1.7;
}

.geo-answer strong {
  color: var(--coord-blue);
}

/* 01 / 网络坐标 UI (横向整行维度) */
.coord-dims-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.coord-dim-row {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 1.25rem 1.5rem;
  display: grid;
  grid-template-columns: 140px 1fr 200px;
  align-items: center;
  gap: 1.5rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.coord-dim-row:hover {
  border-color: var(--coord-blue);
  box-shadow: 0 2px 12px rgba(45, 111, 210, 0.06);
}

.dim-badge {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.dim-node {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 2px solid var(--coord-blue);
  background-color: var(--bg-white);
  flex-shrink: 0;
}

.dim-desc {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.6;
}

.dim-focus {
  font-size: 0.85rem;
  color: var(--node-cyan);
  background-color: var(--light-cyan);
  padding: 0.4rem 0.8rem;
  border-radius: 4px;
  text-align: right;
  font-weight: 600;
}

/* 数据表格通用规范 */
.coord-table-wrap {
  width: 100%;
  overflow-x: auto;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.coord-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

.coord-table th {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-weight: 700;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}

.coord-table td {
  padding: 1.1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-body);
  line-height: 1.6;
  vertical-align: middle;
}

.coord-table tr:last-child td {
  border-bottom: none;
}

.coord-table tr:hover td {
  background-color: #fafbfc;
}

.coord-table .tag-primary {
  display: inline-block;
  font-weight: 700;
  color: var(--coord-blue);
}

.coord-table .tag-cyan {
  color: var(--node-cyan);
  font-weight: 600;
}

/* 03 地区坐标表 */
.region-code-badge {
  font-family: monospace;
  font-weight: 700;
  color: var(--coord-blue);
  background-color: var(--light-blue);
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
  font-size: 0.85rem;
}

/* 07 套餐价格 (核心商业转化区域) */
.pricing-section {
  background-color: var(--bg-white);
}

.pricing-quick-picker {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 0.85rem 1.25rem;
  margin-bottom: 1.75rem;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  font-size: 0.9rem;
}

.quick-picker-title {
  font-weight: 700;
  color: var(--text-primary);
}

.quick-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--text-body);
}

.quick-chip strong {
  color: var(--coord-blue);
  font-weight: 600;
}

/* Desktop 套餐资源坐标表 */
.pricing-table-container {
  display: block;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  text-align: left;
}

.pricing-table th {
  background-color: var(--bg-secondary);
  padding: 1rem 1.25rem;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
}

.pricing-table td {
  padding: 1.25rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: middle;
  font-size: 0.95rem;
}

.pricing-table tr:last-child td {
  border-bottom: none;
}

/* 主力推荐 C3 行视觉强化 */
.pricing-table tr.highlight-plan {
  background-color: var(--light-blue);
  position: relative;
}

.pricing-table tr.highlight-plan td {
  border-top: 2px solid var(--coord-blue);
  border-bottom: 2px solid var(--coord-blue);
}

.pricing-table tr.highlight-plan td:first-child {
  border-left: 4px solid var(--coord-blue);
}

.pricing-table tr.highlight-plan td:last-child {
  border-right: 2px solid var(--coord-blue);
}

.pricing-badge-main {
  display: inline-block;
  background-color: var(--node-cyan);
  color: #FFFFFF;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  border-radius: 3px;
  margin-left: 0.5rem;
  vertical-align: middle;
}

.pricing-badge-sub {
  display: inline-block;
  background-color: #E2E8F0;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.45rem;
  border-radius: 3px;
  margin-left: 0.4rem;
}

.price-val {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
}

.price-val-highlight {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--coord-blue);
}

/* 移动端套餐卡片容器 (默认在大屏隐藏，手机端显示) */
.pricing-mobile-container {
  display: none;
  flex-direction: column;
  gap: 1.25rem;
}

.pricing-mobile-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 1.4rem;
}

.pricing-mobile-card.highlight {
  border: 2px solid var(--coord-blue);
  background-color: var(--light-blue);
}

.mobile-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.mobile-card-coord {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--coord-blue);
}

.mobile-card-title {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.mobile-card-price {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.mobile-card-price.highlight {
  color: var(--coord-blue);
}

.mobile-card-details {
  list-style: none;
  padding: 0;
  margin: 0 0 1.25rem;
  font-size: 0.9rem;
  color: var(--text-body);
}

.mobile-card-details li {
  padding: 0.25rem 0;
  display: flex;
  justify-content: space-between;
  border-bottom: 1px dashed rgba(221, 229, 234, 0.7);
}

/* 08 / 深度评测区域卡片 */
.review-preview-box {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 2rem;
}

.review-preview-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.25rem;
  margin-bottom: 1.5rem;
}

.review-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-bottom: 1.75rem;
}

.review-item {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 1.25rem;
}

.review-item h3 {
  font-size: 1.05rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.review-item p {
  font-size: 0.875rem;
  color: var(--text-body);
  margin-bottom: 0;
}

/* 09 / 文章坐标索引表 */
.article-coord-list {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background-color: var(--bg-white);
}

.article-coord-item {
  display: grid;
  grid-template-columns: 80px 1fr 160px;
  align-items: center;
  padding: 1.35rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  transition: background-color var(--transition-fast);
}

.article-coord-item:last-child {
  border-bottom: none;
}

.article-coord-item:hover {
  background-color: var(--light-blue);
}

.article-coord-code {
  font-family: monospace;
  font-weight: 700;
  font-size: 1rem;
  color: var(--coord-blue);
}

.article-coord-main {
  padding-right: 1.5rem;
}

.article-coord-cat {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--node-cyan);
  margin-bottom: 0.25rem;
  display: inline-block;
}

.article-coord-cat a {
  color: var(--node-cyan);
}

.article-coord-cat a:hover {
  text-decoration: underline;
}

.article-coord-title {
  font-size: 1.075rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.article-coord-title a {
  color: var(--text-primary);
}

.article-coord-title a:hover {
  color: var(--coord-blue);
}

.article-coord-excerpt {
  font-size: 0.9rem;
  color: var(--text-body);
  margin-bottom: 0;
  line-height: 1.5;
}

.article-coord-action {
  text-align: right;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.35rem;
}

.article-read-time {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* 10 / 网络排障顺序表 */
.troubleshoot-flow {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.troubleshoot-step {
  display: grid;
  grid-template-columns: 60px 160px 1fr;
  align-items: center;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  padding: 1rem 1.25rem;
  border-radius: 4px;
}

.step-num {
  font-size: 0.95rem;
  font-weight: 800;
  color: var(--coord-blue);
}

.step-title {
  font-weight: 700;
  color: var(--text-primary);
}

.step-desc {
  font-size: 0.9rem;
  color: var(--text-body);
}

/* 11 / FAQ 坐标问答索引 */
.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.faq-item {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item.active {
  border-color: var(--coord-blue);
}

.faq-trigger {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1.15rem 1.4rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  font-family: var(--font-sans);
}

.faq-question-wrap {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.faq-index-tag {
  font-size: 0.8rem;
  font-family: monospace;
  font-weight: 700;
  color: var(--coord-blue);
  background-color: var(--light-blue);
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
}

.faq-icon {
  font-size: 1.2rem;
  color: var(--text-secondary);
  transition: transform var(--transition-fast);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
  color: var(--coord-blue);
}

.faq-answer {
  display: none;
  padding: 0 1.4rem 1.25rem 3.4rem;
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  display: block;
}

/* ==========================================================================
   Footer (页脚规范：浅蓝灰科技 / 紧凑)
   ========================================================================== */
.site-footer {
  background-color: var(--footer-bg);
  border-top: 1px solid var(--border-color);
  color: var(--footer-text);
  padding: 3rem 0 1.5rem;
  margin-top: auto;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr 1.2fr;
  gap: 2rem;
  padding-bottom: 2.25rem;
  border-bottom: 1px solid var(--border-color);
}

.footer-col-brand h3 {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.footer-brand-desc {
  font-size: 0.875rem;
  color: var(--footer-text);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.footer-col h4 {
  font-size: 0.925rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.85rem;
  letter-spacing: 0.02em;
}

.footer-nav-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-nav-list li {
  margin-bottom: 0.45rem;
}

.footer-nav-list a {
  color: var(--footer-text);
  font-size: 0.875rem;
}

.footer-nav-list a:hover {
  color: var(--coord-blue);
}

.footer-bottom {
  padding-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--footer-text);
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copyright {
  color: var(--footer-text);
}

.footer-friend-links {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.friend-links-title {
  font-weight: 700;
  color: var(--text-primary);
}

.footer-friend-links a {
  color: var(--footer-text);
  font-size: 0.85rem;
}

.footer-friend-links a:hover {
  color: var(--coord-blue);
  text-decoration: underline;
}

/* ==========================================================================
   文章与分类页排版 (Article & Category)
   ========================================================================== */
.article-page-wrap {
  padding: 3rem 0 4.5rem;
}

.article-container {
  max-width: var(--article-width);
  margin: 0 auto;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 3rem 3.5rem;
}

.breadcrumb-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.breadcrumb-nav a {
  color: var(--text-secondary);
}

.breadcrumb-nav a:hover {
  color: var(--coord-blue);
}

.article-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.75rem;
  margin-bottom: 2rem;
}

.article-category-tag {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--node-cyan);
  background-color: var(--light-cyan);
  padding: 0.25rem 0.65rem;
  border-radius: 4px;
  margin-bottom: 0.85rem;
}

.article-title {
  font-size: clamp(1.85rem, 3vw, 2.45rem);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.article-summary-lead {
  font-size: 1.1rem;
  color: var(--text-body);
  line-height: 1.7;
  margin-bottom: 1.25rem;
}

.article-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.meta-item strong {
  color: var(--text-primary);
}

/* 快速结论 (GEO 优先展示) */
.quick-conclusion-box {
  background-color: var(--light-blue);
  border-left: 4px solid var(--coord-blue);
  padding: 1.25rem 1.5rem;
  border-radius: 0 4px 4px 0;
  margin-bottom: 2.25rem;
}

.quick-conclusion-title {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--coord-blue);
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.quick-conclusion-box p {
  font-size: 0.975rem;
  color: var(--text-primary);
  line-height: 1.7;
  margin-bottom: 0;
}

/* 目录 (TOC) */
.article-toc {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 2.5rem;
}

.article-toc-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.article-toc-list {
  list-style: none;
  padding-left: 0;
  margin-bottom: 0;
}

.article-toc-list li {
  margin-bottom: 0.45rem;
  font-size: 0.925rem;
}

.article-toc-list a {
  color: var(--text-body);
}

.article-toc-list a:hover {
  color: var(--coord-blue);
  text-decoration: underline;
}

/* 正文内容排版 */
.article-body h2 {
  font-size: 1.55rem;
  margin-top: 2.75rem;
  margin-bottom: 1rem;
  padding-top: 0.5rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.4rem;
}

.article-body h3 {
  font-size: 1.25rem;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.article-body p {
  margin-bottom: 1.35rem;
  color: var(--text-body);
  line-height: 1.8;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.35rem;
  color: var(--text-body);
  line-height: 1.8;
}

.article-body blockquote {
  border-left: 3px solid var(--node-cyan);
  padding-left: 1.25rem;
  margin: 1.5rem 0;
  color: var(--text-secondary);
  font-style: italic;
}

.article-cta-box {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 1.75rem 2rem;
  margin: 3rem 0 2rem;
  text-align: center;
}

.article-cta-box h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.article-cta-box p {
  font-size: 0.95rem;
  color: var(--text-body);
  margin-bottom: 1.25rem;
}

.article-footer-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border-color);
  padding-top: 1.75rem;
  margin-top: 2.5rem;
  font-size: 0.95rem;
}

/* 分类页样式 */
.category-header {
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  padding: 3rem 0;
  margin-bottom: 3rem;
}

.category-intro {
  font-size: 1.05rem;
  color: var(--text-body);
  max-width: 800px;
  line-height: 1.75;
  margin-top: 1rem;
}

/* 404 页面 */
.page-404 {
  padding: 5rem 0;
  text-align: center;
}

.code-404 {
  font-size: 6rem;
  font-weight: 900;
  color: var(--coord-blue);
  line-height: 1;
  margin-bottom: 1rem;
  font-family: monospace;
}

/* ==========================================================================
   响应式规范 (Mobile-First / Breakpoints)
   测试档位：375, 390, 430, 768, 1024, 1440
   ========================================================================== */

@media (max-width: 1024px) {
  .coord-nav-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .coord-cell:nth-child(2) {
    border-right: none;
  }
  .coord-cell:nth-child(1), .coord-cell:nth-child(2) {
    border-bottom: 1px solid var(--border-color);
  }
  .review-grid {
    grid-template-columns: 1fr;
  }
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 860px) {
  .main-nav, .header-action {
    display: none;
  }
  .mobile-menu-btn {
    display: inline-flex;
  }
  .coord-dim-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .dim-focus {
    text-align: left;
  }
  .article-coord-item {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .article-coord-action {
    align-items: flex-start;
    flex-direction: row;
    justify-content: space-between;
    width: 100%;
  }
  .troubleshoot-step {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }
  .article-container {
    padding: 2rem 1.5rem;
  }
  .footer-top {
    grid-template-columns: 1fr;
    gap: 1.75rem;
  }
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
}

@media (max-width: 680px) {
  .hero-coord-nav {
    display: block;
  }
  .coord-nav-grid {
    grid-template-columns: 1fr;
  }
  .coord-cell {
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  .coord-cell:last-child {
    border-bottom: none;
  }
  /* 隐藏桌面端大表格，切换到移动端专属卡片流 */
  .pricing-table-container {
    display: none;
  }
  .pricing-mobile-container {
    display: flex;
  }
  .hero-section {
    padding: 2.5rem 0 2rem;
  }
  .section {
    padding: 3rem 0;
  }
}

/* ==========================================================================
   无障碍与动画减弱模式 (prefers-reduced-motion)
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}