/* ==================================================
   寰宇云 4.0 - 全球时区通行板 官方样式系统
   纯原生 CSS / 移动优先 / 商务科技浅色 / 无任何外部框架
================================================== */

:root {
  --bg-main: #FAFAF8;
  --bg-white: #FFFFFF;
  --bg-second: #F2F5F4;
  --text-main: #182229;
  --text-body: #505B62;
  --text-muted: #828C91;
  --color-blue: #305E96;
  --color-cyan: #4C8B82;
  --color-orange: #C27A47;
  --color-blue-light: #EEF3F8;
  --color-cyan-light: #EEF5F3;
  --color-orange-light: #F7EFE9;
  --border-color: #E1E6E4;
  --border-subtle: #EBEFEA;
  --footer-bg: #EEF2F0;
  --footer-text: #475258;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace;

  --max-width: 1200px;
  --article-width: 820px;
  --header-height: 70px;
  --transition-fast: 0.2s ease;
  --shadow-subtle: 0 2px 8px rgba(24, 34, 41, 0.04);
  --shadow-card: 0 4px 14px rgba(24, 34, 41, 0.06);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.68;
  font-size: 1rem;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

img, svg {
  vertical-align: middle;
}

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* 容器规范 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.article-container {
  width: 100%;
  max-width: var(--article-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* 按钮规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 6px;
  font-size: 0.9375rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--color-blue);
  color: #FFFFFF;
  border: 1px solid var(--color-blue);
}

.btn-primary:hover {
  background-color: #244b7a;
  border-color: #244b7a;
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-outline {
  background-color: var(--bg-white);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-outline:hover {
  border-color: var(--color-blue);
  color: var(--color-blue);
  background-color: var(--color-blue-light);
}

.btn-cyan {
  background-color: var(--color-cyan);
  color: #FFFFFF;
  border: 1px solid var(--color-cyan);
}

.btn-cyan:hover {
  background-color: #3b6f68;
}

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

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

/* 徽章与标签 */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8125rem;
  padding: 3px 10px;
  border-radius: 4px;
  font-weight: 500;
  line-height: 1.4;
}

.badge-blue {
  background-color: var(--color-blue-light);
  color: var(--color-blue);
  border: 1px solid #D7E3EF;
}

.badge-cyan {
  background-color: var(--color-cyan-light);
  color: var(--color-cyan);
  border: 1px solid #D6E7E4;
}

.badge-orange {
  background-color: var(--color-orange-light);
  color: var(--color-orange);
  border: 1px solid #F0DFD3;
}

.badge-neutral {
  background-color: #ECEFEF;
  color: var(--text-body);
}

/* ==================================================
   Header 导航栏
================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-white);
  height: var(--header-height);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 1px 4px rgba(24, 34, 41, 0.02);
}

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

.brand-wrapper {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo-svg {
  display: block;
  flex-shrink: 0;
}

.brand-titles {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 1.1875rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.01em;
  line-height: 1.2;
}

.brand-sub {
  font-size: 0.6875rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-link {
  position: relative;
  font-size: 0.875rem;
  color: var(--text-body);
  font-weight: 500;
  padding: 8px 2px;
  transition: color var(--transition-fast);
}

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

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

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -15px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-blue);
  border-radius: 2px;
}

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

.mobile-menu-toggle {
  display: none;
  padding: 8px;
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-white);
  align-items: center;
  justify-content: center;
}

.mobile-nav-drawer {
  display: none;
  position: absolute;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
  padding: 16px 24px 24px;
}

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

.mobile-nav-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.mobile-nav-link {
  display: block;
  padding: 10px 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-main);
  border-bottom: 1px solid var(--border-subtle);
}

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

.mobile-drawer-cta {
  margin-top: 18px;
}

/* ==================================================
   Hero 全球时间带区域 (非卡片、横向数据带)
================================================== */
.hero-section {
  padding: 48px 0 56px;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-color);
}

.hero-meta-tag {
  margin-bottom: 16px;
}

.hero-title-group {
  max-width: 900px;
}

.hero-slogan {
  font-size: 2.375rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.hero-sub {
  font-size: 1.0625rem;
  color: var(--color-cyan);
  font-weight: 600;
  letter-spacing: 0.01em;
  margin-bottom: 14px;
}

.hero-h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-blue);
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}

.hero-desc {
  font-size: 0.975rem;
  color: var(--text-body);
  max-width: 820px;
  line-height: 1.7;
  margin-bottom: 26px;
}

.hero-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 40px;
}

/* 全球时间带展示板 (Hero 横向层级带) */
.hero-transit-board {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow-subtle);
}

.transit-board-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  background-color: var(--bg-second);
  border-bottom: 1px solid var(--border-color);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.transit-board-header-left {
  display: flex;
  gap: 20px;
}

.transit-board-header-right {
  display: flex;
  align-items: center;
  gap: 6px;
  color: var(--color-cyan);
}

.transit-belt-row {
  display: grid;
  grid-template-columns: 140px 240px 1fr 140px;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color var(--transition-fast);
}

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

.transit-belt-row:hover {
  background-color: #F8FAF9;
}

.belt-tz-code {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-blue);
  background: var(--color-blue-light);
  padding: 3px 10px;
  border-radius: 4px;
  width: fit-content;
}

.belt-tz-cyan {
  color: var(--color-cyan);
  background: var(--color-cyan-light);
}

.belt-tz-orange {
  color: var(--color-orange);
  background: var(--color-orange-light);
}

.belt-regions {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
}

.belt-purpose {
  font-size: 0.875rem;
  color: var(--text-body);
}

.belt-status {
  text-align: right;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
}

/* ==================================================
   章节模块基础结构 (横向层级、大面积留白)
================================================== */
.page-section {
  padding: 68px 0;
  border-bottom: 1px solid var(--border-color);
}

.page-section:nth-child(even) {
  background-color: var(--bg-second);
}

.section-header {
  margin-bottom: 34px;
}

.section-index-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-blue);
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}

.section-title {
  font-size: 1.625rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -0.015em;
  line-height: 1.35;
  margin-bottom: 10px;
}

.section-subtitle {
  font-size: 0.9375rem;
  color: var(--text-body);
  max-width: 780px;
}

/* ==================================================
   01 / 02 / 03 地区时间带模块 (UTC+8, UTC+9, 美国带)
================================================== */
.timezone-band-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.timezone-band-block {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow-subtle);
}

.tz-band-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 24px;
  background-color: var(--bg-second);
  border-bottom: 1px solid var(--border-color);
}

.tz-band-tag {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-blue);
}

.tz-band-note {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.tz-band-content {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.tz-node-item {
  display: grid;
  grid-template-columns: 160px 1fr 1fr;
  align-items: start;
  gap: 24px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border-subtle);
}

.tz-node-item:last-child {
  padding-bottom: 0;
  border-bottom: none;
}

.tz-node-name {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 4px;
}

.tz-node-desc {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.tz-item-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.field-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-blue);
  letter-spacing: 0.04em;
}

.field-value {
  font-size: 0.875rem;
  color: var(--text-main);
  line-height: 1.55;
}

/* ==================================================
   04 线路表格 (直连、中转、IEPL、IPLC)
================================================== */
.line-table-wrapper {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow-x: auto;
  box-shadow: var(--shadow-subtle);
}

.line-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

.line-table th {
  background-color: var(--bg-second);
  color: var(--text-main);
  font-weight: 600;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}

.line-table td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-body);
  vertical-align: top;
  line-height: 1.6;
}

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

.line-table tr:hover td {
  background-color: #F8FAF9;
}

.line-type-pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--color-blue);
  background: var(--color-blue-light);
  padding: 3px 8px;
  border-radius: 4px;
}

/* ==================================================
   05 / 06 服务地区带 (AI工具 / 流媒体)
================================================== */
.service-band-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.service-band-row {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 18px 24px;
  display: grid;
  grid-template-columns: 180px 1fr 1fr;
  align-items: center;
  gap: 24px;
  transition: all var(--transition-fast);
}

.service-band-row:hover {
  border-color: #C7D4D0;
  box-shadow: var(--shadow-subtle);
  transform: translateY(-1px);
}

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

.service-band-meta {
  font-size: 0.875rem;
  color: var(--text-body);
}

.service-band-tip {
  font-size: 0.84375rem;
  color: var(--color-cyan);
  background: var(--color-cyan-light);
  padding: 6px 12px;
  border-radius: 4px;
}

/* ==================================================
   07 设备使用带 (Windows, macOS, Android, iPhone)
================================================== */
.device-band-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.device-band-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 24px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 16px;
}

.device-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.device-name {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
}

.device-tools {
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.6;
}

.device-features {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.device-link-action {
  font-size: 0.875rem;
  color: var(--color-blue);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.device-link-action:hover {
  text-decoration: underline;
}

/* ==================================================
   08 套餐价格 (使用周期轴 + 主力推荐 + 独立年付带)
================================================== */
.pricing-section {
  background: var(--bg-white);
}

/* 频率轴 */
.frequency-axis-container {
  margin-bottom: 28px;
}

.axis-track {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  position: relative;
  background: var(--bg-second);
  border: 1px solid var(--border-color);
  border-radius: 8px 8px 0 0;
  padding: 12px 0;
}

.axis-node {
  text-align: center;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  position: relative;
}

.axis-node.active-highlight {
  color: var(--color-blue);
  font-weight: 700;
}

.axis-node.active-highlight::after {
  content: "";
  position: absolute;
  bottom: -12px;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 3px;
  background-color: var(--color-blue);
  border-radius: 2px;
}

/* 4档月付阶段展示 */
.frequency-plans-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--border-color);
  border-top: none;
  background: var(--bg-white);
  border-radius: 0 0 8px 8px;
  overflow: hidden;
}

.plan-column {
  padding: 28px 22px;
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 20px;
  transition: background-color var(--transition-fast);
}

.plan-column:last-child {
  border-right: none;
}

.plan-column:hover {
  background-color: #FAFBFB;
}

/* 主力使用突出样式 */
.plan-column.plan-recommended {
  background-color: var(--color-cyan-light);
  border-top: 3px solid var(--color-blue);
  margin-top: -3px;
  position: relative;
  box-shadow: 0 4px 16px rgba(48, 94, 150, 0.08);
}

.plan-head {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.plan-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.plan-name {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
}

.plan-price-box {
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-blue);
  font-family: var(--font-mono);
}

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

.plan-traffic {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
}

.plan-scenarios {
  font-size: 0.8125rem;
  color: var(--text-body);
  line-height: 1.6;
  border-top: 1px dashed var(--border-color);
  padding-top: 12px;
}

/* 独立年度方案使用带 */
.annual-plan-band {
  margin-top: 24px;
  background: #FCFDFD;
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--color-orange);
  border-radius: 8px;
  padding: 22px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.annual-info {
  display: flex;
  align-items: center;
  gap: 24px;
}

.annual-title-group {
  display: flex;
  flex-direction: column;
}

.annual-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
}

.annual-price-group {
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.annual-price {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-orange);
  font-family: var(--font-mono);
}

.annual-traffic {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-body);
  background: var(--color-orange-light);
  padding: 3px 8px;
  border-radius: 4px;
}

.annual-desc {
  font-size: 0.875rem;
  color: var(--text-body);
}

/* ==================================================
   09 深度评测区域展示
================================================== */
.review-preview-band {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 32px;
  box-shadow: var(--shadow-subtle);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.review-meta-row {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.review-headline {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.4;
}

.review-excerpt {
  font-size: 0.9375rem;
  color: var(--text-body);
  line-height: 1.7;
}

.review-toc-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 4px;
}

.review-toc-pill {
  font-size: 0.8125rem;
  color: var(--text-body);
  background: var(--bg-second);
  padding: 4px 10px;
  border-radius: 4px;
  border: 1px solid var(--border-subtle);
}

/* ==================================================
   10 时间带内容流 (文章区域)
================================================== */
.content-stream-container {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.stream-band-group {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow-subtle);
}

.stream-band-header {
  padding: 12px 24px;
  background-color: var(--bg-second);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.stream-band-title {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-blue);
  display: flex;
  align-items: center;
  gap: 8px;
}

.stream-article-row {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  transition: background-color var(--transition-fast);
}

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

.stream-article-row:hover {
  background-color: #FAFBFB;
}

.stream-article-info {
  display: flex;
  flex-direction: column;
  gap: 6px;
  max-width: 820px;
}

.stream-article-title {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--text-main);
  transition: color var(--transition-fast);
}

.stream-article-row:hover .stream-article-title {
  color: var(--color-blue);
}

.stream-article-desc {
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.6;
}

.stream-article-action {
  flex-shrink: 0;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-blue);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* ==================================================
   11 网络排障步骤流
================================================== */
.troubleshoot-flow {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 28px;
  box-shadow: var(--shadow-subtle);
}

.troubleshoot-step-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  position: relative;
}

.troubleshoot-step-item {
  display: grid;
  grid-template-columns: 44px 180px 1fr;
  align-items: start;
  gap: 16px;
  padding: 14px 16px;
  background: var(--bg-second);
  border-radius: 6px;
  border: 1px solid var(--border-subtle);
}

.step-num {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-blue);
  background: var(--color-blue-light);
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
}

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

.step-desc {
  font-size: 0.875rem;
  color: var(--text-body);
  line-height: 1.6;
}

/* ==================================================
   12 FAQ 常见问题 (手风琴)
================================================== */
.faq-accordion-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

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

.faq-question-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  text-align: left;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-main);
  background: none;
}

.faq-question-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.faq-index {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-blue);
  background: var(--color-blue-light);
  padding: 2px 6px;
  border-radius: 4px;
}

.faq-toggle-icon {
  font-size: 1.25rem;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
}

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

.faq-answer-panel {
  display: none;
  padding: 0 20px 18px 48px;
  font-size: 0.9rem;
  color: var(--text-body);
  line-height: 1.7;
  border-top: 1px dashed var(--border-subtle);
  margin-top: -4px;
}

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

/* ==================================================
   Footer 页脚 (浅灰青商务科技、紧凑、右侧友情链接)
================================================== */
.site-footer {
  background-color: var(--footer-bg);
  color: var(--footer-text);
  border-top: 1px solid var(--border-color);
  padding: 44px 0 24px;
  font-size: 0.875rem;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1.5fr;
  gap: 32px;
  margin-bottom: 36px;
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-brand-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-main);
}

.footer-brand-sub {
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.footer-col-title {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 12px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

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

.footer-links a:hover {
  color: var(--color-blue);
}

.footer-cta-col {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 20px;
  border-top: 1px solid rgba(24, 34, 41, 0.08);
  font-size: 0.8125rem;
  color: var(--text-muted);
}

.footer-friendly-links {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.friendly-links-label {
  font-weight: 600;
  color: var(--text-body);
}

.footer-friendly-links a {
  color: var(--text-body);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition-fast);
}

.footer-friendly-links a:hover {
  color: var(--color-blue);
}

/* ==================================================
   文章详情页规范 (浅色商务、独立白底正文、GEO问答结构)
================================================== */
.article-page-header {
  padding: 36px 0 24px;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-white);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-bottom: 14px;
  flex-wrap: wrap;
}

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

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

.breadcrumbs span.current {
  color: var(--text-body);
  font-weight: 500;
}

.article-main-h1 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.3;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.8125rem;
  color: var(--text-muted);
  padding-top: 12px;
  border-top: 1px solid var(--border-subtle);
}

.article-body-wrapper {
  padding: 40px 0 60px;
}

.article-content {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 40px 48px;
  box-shadow: var(--shadow-subtle);
}

/* GEO 快速结论高亮框 */
.quick-conclusion-box {
  background: var(--color-cyan-light);
  border: 1px solid #CDE1DC;
  border-left: 4px solid var(--color-cyan);
  border-radius: 6px;
  padding: 18px 22px;
  margin-bottom: 32px;
}

.quick-conclusion-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-cyan);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.quick-conclusion-text {
  font-size: 0.9375rem;
  color: var(--text-main);
  line-height: 1.68;
}

/* 文章目录 */
.article-toc-box {
  background: var(--bg-second);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 20px 24px;
  margin-bottom: 36px;
}

.toc-title {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 12px;
}

.toc-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-left: 8px;
}

.toc-item a {
  font-size: 0.875rem;
  color: var(--text-body);
  transition: color var(--transition-fast);
}

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

/* 文章排版样式 */
.article-content h2 {
  font-size: 1.4375rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 40px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-subtle);
  line-height: 1.35;
}

.article-content h3 {
  font-size: 1.1875rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 28px;
  margin-bottom: 12px;
}

.article-content p {
  font-size: 0.975rem;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 18px;
}

.article-content ul, .article-content ol {
  margin-bottom: 20px;
  padding-left: 24px;
}

.article-content ul li {
  list-style-type: disc;
  margin-bottom: 8px;
  font-size: 0.95rem;
  line-height: 1.7;
}

.article-content ol li {
  list-style-type: decimal;
  margin-bottom: 8px;
  font-size: 0.95rem;
  line-height: 1.7;
}

.article-content blockquote {
  border-left: 4px solid var(--color-blue);
  background: var(--color-blue-light);
  padding: 14px 20px;
  border-radius: 4px;
  margin-bottom: 22px;
  font-size: 0.9375rem;
  color: var(--text-main);
}

.article-content code {
  font-family: var(--font-mono);
  background: var(--bg-second);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.875rem;
  color: var(--color-blue);
  border: 1px solid var(--border-subtle);
}

.article-content pre {
  background: #20272B;
  color: #ECEFEF;
  padding: 18px 22px;
  border-radius: 6px;
  overflow-x: auto;
  margin-bottom: 22px;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
}

.article-content pre code {
  background: transparent;
  color: inherit;
  border: none;
  padding: 0;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 26px;
  font-size: 0.9rem;
}

.article-content table th {
  background: var(--bg-second);
  color: var(--text-main);
  padding: 12px 16px;
  border: 1px solid var(--border-color);
  text-align: left;
}

.article-content table td {
  padding: 12px 16px;
  border: 1px solid var(--border-color);
  color: var(--text-body);
}

/* 文章底部导航条 */
.article-nav-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 36px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

.article-nav-prev, .article-nav-next {
  display: flex;
  flex-direction: column;
  gap: 4px;
  max-width: 45%;
}

.article-nav-next {
  text-align: right;
  margin-left: auto;
}

.article-nav-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
}

.article-nav-link {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-blue);
  line-height: 1.4;
}

.article-nav-link:hover {
  text-decoration: underline;
}

.article-back-category {
  margin-top: 24px;
  text-align: center;
}

/* ==================================================
   分类页列表与信息规范
================================================== */
.category-header {
  padding: 44px 0 28px;
  background: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
}

.category-title {
  font-size: 1.875rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
}

.category-desc {
  font-size: 0.95rem;
  color: var(--text-body);
  max-width: 760px;
  line-height: 1.7;
}

.category-articles-list {
  padding: 40px 0 60px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.category-article-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 24px 28px;
  box-shadow: var(--shadow-subtle);
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.category-article-card:hover {
  border-color: #C5D3CE;
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.category-article-title {
  font-size: 1.1875rem;
  font-weight: 700;
  color: var(--text-main);
}

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

.category-article-summary {
  font-size: 0.9rem;
  color: var(--text-body);
  line-height: 1.65;
}

.category-article-meta {
  font-size: 0.8125rem;
  color: var(--text-muted);
  display: flex;
  gap: 16px;
  margin-top: 6px;
}

/* ==================================================
   单页基础排版 (About / Terms / Privacy / 404 / Sitemap)
================================================== */
.page-standard-wrapper {
  padding: 44px 0 60px;
}

.page-standard-content {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 40px 48px;
  box-shadow: var(--shadow-subtle);
}

.page-standard-content h1 {
  font-size: 1.875rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.page-standard-content h2 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 32px;
  margin-bottom: 12px;
}

.page-standard-content p {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.75;
  margin-bottom: 16px;
}

.page-standard-content ul {
  padding-left: 20px;
  margin-bottom: 20px;
}

.page-standard-content li {
  list-style: disc;
  margin-bottom: 6px;
  font-size: 0.9375rem;
}

/* 404 页面特别样式 */
.notfound-box {
  text-align: center;
  padding: 60px 20px;
}

.notfound-code {
  font-family: var(--font-mono);
  font-size: 5rem;
  font-weight: 800;
  color: var(--color-blue);
  line-height: 1;
  margin-bottom: 12px;
}

.notfound-msg {
  font-size: 1.25rem;
  color: var(--text-main);
  font-weight: 600;
  margin-bottom: 24px;
}

.notfound-links {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ==================================================
   响应式设计 (Media Queries)
   针对 1440, 1024, 768, 430, 390, 375 逐级调校
================================================== */
@media (max-width: 1024px) {
  .desktop-nav {
    display: none;
  }

  .mobile-menu-toggle {
    display: inline-flex;
  }

  .footer-top {
    grid-template-columns: 1fr 1fr 1fr;
    gap: 24px;
  }

  .footer-brand-col {
    grid-column: span 3;
  }

  .footer-cta-col {
    grid-column: span 3;
  }

  .transit-belt-row {
    grid-template-columns: 110px 180px 1fr 100px;
    padding: 14px 16px;
  }

  .frequency-plans-grid {
    grid-template-columns: 1fr 1fr;
  }

  .plan-column {
    border-right: none;
    border-bottom: 1px solid var(--border-subtle);
  }

  .axis-track {
    grid-template-columns: repeat(2, 1fr);
    row-gap: 8px;
  }
}

@media (max-width: 768px) {
  .hero-slogan {
    font-size: 1.875rem;
  }

  .hero-h1 {
    font-size: 1.125rem;
  }

  .transit-belt-row {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .belt-status {
    text-align: left;
  }

  .tz-node-item {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .service-band-row {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .device-band-grid {
    grid-template-columns: 1fr;
  }

  .annual-plan-band {
    flex-direction: column;
    align-items: flex-start;
  }

  .annual-info {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .stream-article-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .troubleshoot-step-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .article-content {
    padding: 24px 20px;
  }

  .page-standard-content {
    padding: 24px 20px;
  }

  .footer-top {
    grid-template-columns: 1fr;
  }

  .footer-brand-col, .footer-cta-col {
    grid-column: span 1;
  }

  .footer-bottom {
    flex-direction: column-reverse;
    align-items: flex-start;
    gap: 14px;
  }
}

/* 针对手机端 375 / 390 / 430 的单列周期套餐重新排序与优化 */
@media (max-width: 640px) {
  /* 移动端套餐使用垂直单列，顺序为：主力推荐 -> 日常 -> 轻度 -> 高频 -> 长期备用 */
  .axis-track {
    display: none;
  }

  .frequency-plans-grid {
    display: flex;
    flex-direction: column;
    border: none;
    background: transparent;
    gap: 14px;
  }

  .plan-column {
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 20px;
  }

  /* 调整排序：主力推荐排在最前 */
  .plan-column.plan-recommended {
    order: 1;
    border: 2px solid var(--color-blue);
    background: var(--color-cyan-light);
  }

  .plan-column.plan-daily {
    order: 2;
  }

  .plan-column.plan-light {
    order: 3;
  }

  .plan-column.plan-heavy {
    order: 4;
  }

  .annual-plan-band {
    order: 5;
    margin-top: 14px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-actions .btn {
    width: 100%;
  }

  .header-cta {
    display: none;
  }

  .brand-sub {
    display: none;
  }

  .faq-answer-panel {
    padding-left: 20px;
  }
}

/* ==================================================
   减少动画支持 (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;
  }
}