/* ==================================================
   泰山机场 · 品牌官方网站样式表
   主题：海拔分层系统 (Altitude Layering System)
   配色：雾白 #F5F6F3 | 松柏绿 #35685B | 岩石橙 #B8744D | 石墨灰 #202724
   ================================================== */

:root {
  --bg-main: #F5F6F3;
  --bg-white: #FFFFFF;
  --bg-secondary: #EFF2EE;
  --text-main: #202724;
  --text-body: #53605A;
  --text-muted: #89918D;
  --pine-green: #35685B;
  --pine-dark: #274D44;
  --rock-orange: #B8744D;
  --green-light: #EAF0EC;
  --orange-light: #F4ECE7;
  --border-color: #DDE2DD;
  --footer-bg: #E9EEEA;
  --footer-text: #424D47;
  
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --max-width: 1200px;
  --max-article-width: 800px;
  --header-height: 70px;
  --radius-sm: 4px;
  --radius-md: 8px;
  --transition-fast: 0.2s ease;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.85;
  font-size: 1.0625rem; /* 17px */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 链接与排版 */
a {
  color: var(--pine-green);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--pine-dark);
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.35;
}

h1 {
  font-size: 2.875rem; /* 46px */
  letter-spacing: -0.02em;
}

h2 {
  font-size: 2rem; /* 32px */
  letter-spacing: -0.01em;
  margin-bottom: 1.25rem;
}

h3 {
  font-size: 1.375rem; /* 22px */
  margin-bottom: 0.75rem;
}

p {
  margin-bottom: 1.25rem;
}

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

ul, ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}

li {
  margin-bottom: 0.5rem;
}

.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 {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.625rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-arrow {
  transition: transform var(--transition-fast);
}

.btn:hover .btn-arrow {
  transform: translateX(3px);
}

.btn-primary {
  background-color: var(--pine-green);
  color: #FFFFFF;
}

.btn-primary:hover {
  background-color: var(--pine-dark);
  color: #FFFFFF;
}

.btn-secondary {
  background-color: transparent;
  color: var(--pine-green);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-secondary);
  border-color: var(--pine-green);
  color: var(--pine-dark);
}

.btn-accent {
  background-color: var(--rock-orange);
  color: #FFFFFF;
}

.btn-accent:hover {
  background-color: #9f5f3b;
  color: #FFFFFF;
}

/* 标签与徽章 */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.625rem;
  font-size: 0.8125rem;
  font-weight: 600;
  border-radius: 2px;
}

.badge-green {
  background-color: var(--green-light);
  color: var(--pine-dark);
  border: 1px solid rgba(53, 104, 91, 0.2);
}

.badge-orange {
  background-color: var(--orange-light);
  color: var(--rock-orange);
  border: 1px solid rgba(184, 116, 77, 0.25);
}

.section-label {
  display: inline-block;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--pine-green);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

/* ==================================================
   Header 导航栏
   ================================================== */
.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-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 0.875rem;
  text-decoration: none;
}

.brand-logo-svg {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
}

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

.brand-name {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.2;
}

.brand-tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.2;
  letter-spacing: 0.02em;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 1.35rem;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-body);
  font-weight: 500;
  padding: 0.5rem 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--pine-green);
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--pine-green);
}

.header-cta-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.mobile-menu-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.75rem;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
}

.mobile-drawer {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  padding: 1.5rem;
  box-shadow: 0 10px 20px rgba(0,0,0,0.05);
  z-index: 999;
}

.mobile-drawer.is-open {
  display: block;
}

.mobile-nav-list {
  list-style: none;
  padding: 0;
  margin: 0 0 1.25rem 0;
}

.mobile-nav-list li {
  margin-bottom: 0.75rem;
}

.mobile-nav-list a {
  display: block;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-main);
  padding: 0.5rem 0;
  border-bottom: 1px dashed var(--border-color);
}

/* ==================================================
   Hero 区域与网络海拔剖面
   ================================================== */
.hero-section {
  padding: 3.5rem 0 3rem 0;
  background: linear-gradient(180deg, var(--bg-white) 0%, var(--bg-main) 100%);
  border-bottom: 1px solid var(--border-color);
}

.hero-content-wrapper {
  max-width: 980px;
  margin: 0 auto;
}

.hero-meta-top {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.hero-slogan-main {
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--pine-green);
  margin-bottom: 0.5rem;
}

.hero-title {
  font-size: 2.75rem; /* 44px-48px */
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 0.75rem;
  line-height: 1.25;
}

.hero-subheading {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--rock-orange);
  margin-bottom: 1rem;
  letter-spacing: 0.02em;
}

.hero-lead-text {
  font-size: 1.125rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 1.75rem;
  max-width: 900px;
}

.hero-cta-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
  margin-bottom: 2.5rem;
}

/* 网络海拔剖面 UI (Hero 下半部分) */
.altitude-profile-container {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2rem 2.25rem;
  margin-top: 1.5rem;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.02);
}

.altitude-profile-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
  margin-bottom: 1.5rem;
}

.altitude-profile-header h3 {
  margin-bottom: 0;
  font-size: 1.1875rem;
}

.altitude-layers-system {
  display: flex;
  flex-direction: column-reverse; /* 从下往上：山脚到主峰 */
  position: relative;
  padding-left: 2.5rem;
}

.altitude-layers-system::before {
  content: "";
  position: absolute;
  left: 11px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: linear-gradient(180deg, var(--pine-green) 0%, var(--border-color) 100%);
}

.altitude-layer-item {
  position: relative;
  padding: 1rem 0;
  border-bottom: 1px dashed var(--border-color);
  display: grid;
  grid-template-columns: 90px 140px 1fr;
  align-items: baseline;
  gap: 1.25rem;
  transition: background-color var(--transition-fast);
}

.altitude-layer-item:first-child {
  border-bottom: none;
}

.altitude-layer-item::before {
  content: "";
  position: absolute;
  left: -2.5rem;
  top: 1.55rem;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--bg-white);
  border: 2px solid var(--pine-green);
  z-index: 2;
}

.altitude-layer-item.is-peak::before {
  background-color: var(--rock-orange);
  border-color: var(--rock-orange);
  box-shadow: 0 0 0 3px var(--orange-light);
}

.layer-code {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--pine-green);
  font-family: monospace;
}

.altitude-layer-item.is-peak .layer-code {
  color: var(--rock-orange);
}

.layer-title {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text-main);
}

.layer-desc {
  font-size: 0.9375rem;
  color: var(--text-body);
}

/* ==================================================
   通用 Section 规范
   ================================================== */
.page-section {
  padding: 4.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

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

.section-intro p.lead {
  font-size: 1.125rem;
  color: var(--text-body);
  max-width: 860px;
}

/* ==================================================
   01 / 基础接入：纵向检查线
   ================================================== */
.vertical-checklist {
  display: flex;
  flex-direction: column;
  position: relative;
  padding-left: 3rem;
  max-width: 900px;
  margin: 0 auto;
}

.vertical-checklist::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 20px;
  bottom: 20px;
  width: 2px;
  background-color: var(--border-color);
}

.check-step-item {
  position: relative;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border-color);
}

.check-step-item:last-child {
  border-bottom: none;
}

.step-node-marker {
  position: absolute;
  left: -3rem;
  top: 1.25rem;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background-color: var(--bg-white);
  border: 2px solid var(--pine-green);
  color: var(--pine-green);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  font-weight: 700;
  z-index: 2;
}

.step-content-box h3 {
  font-size: 1.1875rem;
  margin-bottom: 0.35rem;
}

.step-content-box p {
  font-size: 0.96875rem;
  color: var(--text-body);
  margin-bottom: 0.5rem;
}

.step-check-details {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}

/* ==================================================
   02 / 线路海拔：真实 HTML 技术表
   ================================================== */
.tech-table-wrapper {
  overflow-x: auto;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-top: 1.5rem;
}

.tech-data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.96875rem;
}

.tech-data-table th,
.tech-data-table td {
  padding: 1.125rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  vertical-align: top;
}

.tech-data-table th {
  background-color: var(--bg-secondary);
  color: var(--text-main);
  font-weight: 700;
  font-size: 0.9375rem;
  letter-spacing: 0.02em;
}

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

.tech-data-table tr:hover td {
  background-color: rgba(234, 240, 236, 0.4);
}

.line-badge {
  font-weight: 700;
  color: var(--pine-green);
}

/* ==================================================
   03 / 节点高度索引
   ================================================== */
.node-index-list {
  display: flex;
  flex-direction: column;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
}

.node-index-row {
  display: grid;
  grid-template-columns: 100px 140px 1.5fr 1.5fr;
  align-items: center;
  padding: 1.125rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  gap: 1rem;
}

.node-index-row:last-child {
  border-bottom: none;
}

.node-index-row.is-header {
  background-color: var(--bg-secondary);
  font-weight: 700;
  color: var(--text-main);
  font-size: 0.9375rem;
}

.node-code {
  font-family: monospace;
  font-weight: 700;
  color: var(--pine-green);
}

.node-region {
  font-weight: 700;
  color: var(--text-main);
}

/* ==================================================
   04 / AI应用层：应用高度表
   ================================================== */
.ai-app-table-wrapper {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  overflow-x: auto;
}

.ai-app-row {
  display: grid;
  grid-template-columns: 180px 1.2fr 1.5fr;
  padding: 1.125rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  gap: 1rem;
  align-items: center;
}

.ai-app-row:last-child {
  border-bottom: none;
}

.ai-app-row.is-header {
  background-color: var(--bg-secondary);
  font-weight: 700;
  color: var(--text-main);
}

.ai-tool-name {
  font-weight: 700;
  color: var(--text-main);
}

/* ==================================================
   05 / 流媒体层
   ================================================== */
.stream-list-wrapper {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
}

.stream-row {
  display: grid;
  grid-template-columns: 160px 1.2fr 1.5fr;
  padding: 1.125rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  gap: 1rem;
  align-items: center;
}

.stream-row:last-child {
  border-bottom: none;
}

.stream-row.is-header {
  background-color: var(--bg-secondary);
  font-weight: 700;
  color: var(--text-main);
}

.stream-platform-name {
  font-weight: 700;
  color: var(--text-main);
}

/* ==================================================
   06 / 客户端：设备接入层
   ================================================== */
.device-access-system {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.75rem;
}

.device-layer-block {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.75rem;
}

.device-layer-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 1.25rem;
  font-size: 1.1875rem;
}

.device-item-row {
  padding: 1rem 0;
  border-bottom: 1px dashed var(--border-color);
}

.device-item-row:last-child {
  border-bottom: none;
}

.device-item-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.35rem;
}

.device-name {
  font-weight: 700;
  color: var(--text-main);
}

.device-direction {
  font-size: 0.9375rem;
  color: var(--text-body);
}

/* ==================================================
   07 / 套餐等级：核心海拔轴方案
   ================================================== */
.pricing-section {
  background-color: var(--bg-white);
}

.pricing-quick-selector {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.625rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.875rem 1.25rem;
  margin-bottom: 2rem;
  font-size: 0.9375rem;
}

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

.quick-item-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  padding: 0.25rem 0.625rem;
  border-radius: 2px;
  color: var(--text-body);
  font-size: 0.875rem;
}

.pricing-altitude-container {
  position: relative;
  display: flex;
  flex-direction: column-reverse; /* 从山脚往上到云顶 */
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-main);
  padding-left: 160px; /* 左侧留给纵向海拔轴 */
}

.pricing-vertical-axis {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 160px;
  background-color: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column-reverse; /* 底部山脚，顶部云顶 */
  justify-content: space-around;
  padding: 1.5rem 1rem;
}

.axis-step {
  display: flex;
  flex-direction: column;
  position: relative;
  padding-left: 1.25rem;
}

.axis-step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--pine-green);
}

.axis-step.is-peak::before {
  background-color: var(--rock-orange);
  box-shadow: 0 0 0 2px var(--orange-light);
}

.axis-step-name {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-main);
}

.axis-step-alt {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.pricing-tier-row {
  display: grid;
  grid-template-columns: 160px 140px 1.5fr 150px;
  align-items: center;
  padding: 1.75rem 2rem;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  gap: 1.5rem;
  position: relative;
  transition: background-color var(--transition-fast);
}

.pricing-tier-row:first-child {
  border-bottom: none;
}

/* 主峰方案：唯一主推高亮 */
.pricing-tier-row.is-featured-peak {
  background-color: var(--green-light);
  border-left: 4px solid var(--pine-green);
}

.tier-name-box h3 {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.tier-traffic-tag {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.tier-price-box {
  display: flex;
  flex-direction: column;
}

.price-num {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.1;
}

.pricing-tier-row.is-featured-peak .price-num {
  color: var(--pine-dark);
}

.price-cycle {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.tier-desc-box {
  font-size: 0.9375rem;
  color: var(--text-body);
}

.tier-desc-box strong {
  color: var(--text-main);
}

/* 独立年付备用方案 */
.backup-plan-container {
  margin-top: 1.75rem;
  background-color: var(--bg-secondary);
  border: 1px dashed var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.5rem 2rem;
  display: grid;
  grid-template-columns: 240px 160px 1fr 150px;
  align-items: center;
  gap: 1.5rem;
}

.backup-plan-container h3 {
  font-size: 1.1875rem;
  margin-bottom: 0.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* ==================================================
   08 / 泰山机场深度评测导读区
   ================================================== */
.review-highlight-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 2.25rem;
  border-left: 4px solid var(--pine-green);
}

.review-meta-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1rem;
  margin-bottom: 1.25rem;
}

.review-point-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}

.review-point-item {
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  padding: 1.125rem;
  border-radius: 2px;
}

.review-point-item h4 {
  font-size: 1rem;
  color: var(--text-main);
  margin-bottom: 0.35rem;
}

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

/* ==================================================
   09 / 海拔文章索引 UI
   ================================================== */
.altitude-article-index {
  position: relative;
  display: flex;
  flex-direction: column;
  padding-left: 2rem;
  border-left: 2px solid var(--pine-green);
}

.article-index-item {
  position: relative;
  padding: 1.5rem 0 1.5rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: grid;
  grid-template-columns: 80px 1fr 140px;
  align-items: baseline;
  gap: 1.5rem;
  transition: background-color var(--transition-fast);
}

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

.article-index-item::before {
  content: "";
  position: absolute;
  left: -2rem;
  top: 1.85rem;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--bg-white);
  border: 2px solid var(--pine-green);
  transform: translateX(-50%);
}

.article-alt-code {
  font-family: monospace;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--pine-green);
}

.article-body-col h3 {
  font-size: 1.1875rem;
  margin-bottom: 0.35rem;
}

.article-body-col h3 a {
  color: var(--text-main);
}

.article-body-col h3 a:hover {
  color: var(--pine-green);
}

.article-excerpt {
  font-size: 0.9375rem;
  color: var(--text-body);
  margin-bottom: 0.5rem;
}

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

.article-read-time {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ==================================================
   10 / 网络排障：8层排障顺序
   ================================================== */
.troubleshooting-stepper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.troubleshoot-layer-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  position: relative;
}

.layer-level-tag {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--pine-green);
  margin-bottom: 0.25rem;
  font-family: monospace;
}

.troubleshoot-layer-card h3 {
  font-size: 1.125rem;
  margin-bottom: 0.5rem;
}

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

.troubleshoot-notice-box {
  margin-top: 1.75rem;
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--pine-green);
  padding: 1rem 1.25rem;
  font-size: 0.9375rem;
}

/* ==================================================
   11 / 常见问题 (FAQ) 手风琴
   ================================================== */
.faq-accordion-container {
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border-color);
}

.faq-trigger {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 0;
  background: none;
  border: none;
  text-align: left;
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
  cursor: pointer;
  font-family: var(--font-family);
  gap: 1rem;
}

.faq-trigger:hover {
  color: var(--pine-green);
}

.faq-icon {
  font-size: 1.35rem;
  font-weight: 400;
  color: var(--pine-green);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.faq-item.is-open .faq-icon {
  transform: rotate(45deg);
}

.faq-panel {
  display: none;
  padding-bottom: 1.25rem;
  font-size: 1rem;
  color: var(--text-body);
}

.faq-item.is-open .faq-panel {
  display: block;
}

/* ==================================================
   文章内页与分类页布局
   ================================================== */
.article-header {
  padding: 3rem 0 2rem 0;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.breadcrumbs a {
  color: var(--text-muted);
}

.breadcrumbs a:hover {
  color: var(--pine-green);
}

.breadcrumbs-sep {
  color: var(--border-color);
}

.article-title {
  font-size: 2.375rem; /* 38px */
  margin-bottom: 1rem;
  line-height: 1.3;
}

.article-meta-info {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

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

.article-lead-box {
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--pine-green);
  padding: 1.125rem 1.5rem;
  font-size: 1.0625rem;
  color: var(--text-main);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.article-main-container {
  max-width: var(--max-article-width);
  margin: 3rem auto;
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 3rem 2.5rem;
}

/* GEO: 快速结论卡片 */
.geo-conclusion-box {
  background-color: var(--green-light);
  border: 1px solid rgba(53, 104, 91, 0.25);
  border-radius: var(--radius-sm);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2rem;
}

.geo-conclusion-box h3 {
  font-size: 1.125rem;
  color: var(--pine-dark);
  margin-bottom: 0.5rem;
}

.geo-conclusion-box p {
  font-size: 0.96875rem;
  color: var(--text-main);
  margin-bottom: 0;
}

/* 本文目录 (TOC) */
.toc-box {
  background-color: var(--bg-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2.5rem;
}

.toc-box h3 {
  font-size: 1.0625rem;
  margin-bottom: 0.75rem;
  color: var(--text-main);
}

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

.toc-list li {
  margin-bottom: 0.35rem;
  font-size: 0.9375rem;
}

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

.toc-list a:hover {
  color: var(--pine-green);
  text-decoration: underline;
}

/* 正文排版 */
.article-body h2 {
  font-size: 1.625rem;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

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

.article-body p {
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--text-body);
  margin-bottom: 1.35rem;
}

.article-body ul, .article-body ol {
  margin-bottom: 1.35rem;
}

.article-body li {
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--text-body);
}

.article-nav-pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border-color);
  margin-top: 3rem;
  padding-top: 1.5rem;
  font-size: 0.9375rem;
}

/* 分类页列表 */
.category-article-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 2rem;
}

.category-article-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.75rem;
}

.category-article-card h2 {
  font-size: 1.375rem;
  margin-bottom: 0.5rem;
}

.category-article-card h2 a {
  color: var(--text-main);
}

.category-article-card h2 a:hover {
  color: var(--pine-green);
}

/* ==================================================
   Footer 页脚 (浅灰绿 #E9EEEA, 高度 250px-320px)
   ================================================== */
.site-footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 1.5rem 0;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-brand-col h4 {
  font-size: 1.25rem;
  color: var(--text-main);
  margin-bottom: 0.5rem;
}

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

.footer-nav-col h5 {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 0.875rem;
  letter-spacing: 0.02em;
}

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

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

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

.footer-link-list a:hover {
  color: var(--pine-dark);
  text-decoration: underline;
}

/* 底部最严格固定友情链接与版权 */
.footer-bottom-bar {
  border-top: 1px solid rgba(0, 0, 0, 0.08);
  padding-top: 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.84375rem;
}

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

.footer-friend-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.875rem;
}

.friend-links-title {
  color: var(--text-main);
  font-weight: 600;
}

.footer-friend-links a {
  color: var(--footer-text);
}

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

/* ==================================================
   404 页面
   ================================================== */
.error-page-container {
  min-height: 60vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 1.5rem;
}

.error-code {
  font-size: 5rem;
  font-weight: 900;
  color: var(--pine-green);
  line-height: 1;
  margin-bottom: 1rem;
}

.error-message {
  font-size: 1.35rem;
  color: var(--text-main);
  margin-bottom: 2rem;
}

/* ==================================================
   响应式适配 (Desktop -> 1024 -> 768 -> 430 -> 390 -> 375)
   ================================================== */
@media (max-width: 1024px) {
  .desktop-nav {
    display: none;
  }
  .mobile-menu-btn {
    display: inline-block;
  }
  .pricing-altitude-container {
    padding-left: 0;
  }
  .pricing-vertical-axis {
    display: none;
  }
  .pricing-tier-row {
    grid-template-columns: 140px 120px 1fr 140px;
    gap: 1rem;
    padding: 1.25rem;
  }
  .backup-plan-container {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  .footer-top-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  body {
    font-size: 1rem;
  }
  h1 {
    font-size: 2.125rem;
  }
  h2 {
    font-size: 1.625rem;
  }
  .hero-title {
    font-size: 2rem;
  }
  .altitude-layer-item {
    grid-template-columns: 1fr;
    gap: 0.25rem;
  }
  .node-index-row {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }
  .ai-app-row {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }
  .stream-row {
    grid-template-columns: 1fr;
    gap: 0.35rem;
  }
  .device-access-system {
    grid-template-columns: 1fr;
  }
  .pricing-altitude-container {
    flex-direction: column;
  }
  .tier-main-peak {
    order: 1;
  }
  .tier-mid-mountain {
    order: 2;
  }
  .tier-mountain-foot {
    order: 3;
  }
  .tier-cloud-summit {
    order: 4;
  }
  .pricing-tier-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
  .article-index-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }
  .article-side-col {
    align-items: flex-start;
    text-align: left;
  }
  .article-main-container {
    padding: 1.75rem 1.25rem;
    margin: 1.5rem auto;
  }
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
  .footer-bottom-bar {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 430px) {
  .hero-cta-buttons {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta-buttons .btn {
    width: 100%;
  }
  .altitude-profile-container {
    padding: 1.25rem;
  }
  .vertical-checklist {
    padding-left: 2.25rem;
  }
  .step-node-marker {
    left: -2.25rem;
    width: 26px;
    height: 26px;
    font-size: 0.75rem;
  }
}

/* 无障碍：关闭非必要动效 */
@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;
  }
}