/* ==========================================================================
   River VPN - 流线分流系统 (Stream Distribution System)
   Version: 1.0.0
   Language: Simplified Chinese
   Design: Editorial Tech / Minimalist Stream / Cool White & River Stone Blue
   ========================================================================== */

/* --- 1. CSS 变量与设计令牌 --- */
:root {
  /* 背景体系 */
  --bg-main: #F7F9F8;
  --bg-white: #FFFFFF;
  --bg-secondary: #F1F4F3;
  --bg-light-blue: #EDF2F3;
  --bg-light-green: #EDF3F0;
  
  /* 文字体系 */
  --text-main: #1D282D;
  --text-body: #58666B;
  --text-muted: #859196;
  
  /* 品牌与分流强调色 (20% 蓝灰/深青 + 10% 陶土橙) */
  --color-river-blue: #446B78;
  --color-deep-blue: #355763;
  --color-deep-cyan: #47786D;
  --color-deep-green: #3A635A;
  --color-terracotta: #B97852;
  --color-terracotta-hover: #A36440;
  
  /* 边框与流线结构 */
  --color-border: #DDE4E3;
  --color-border-subtle: #E8EEEC;
  --color-line: #CCD6D4;
  --color-node-active: #355763;
  
  /* 页脚与系统色 */
  --color-footer-bg: #EDF1F0;
  --color-footer-text: #46535A;

  /* 排版尺寸 */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --font-size-base: 16px;
  --line-height-base: 1.8;
  
  /* 布局宽度 */
  --container-max: 1200px;
  --article-max: 820px;
  --header-height: 70px;
  
  /* 圆角与阴影 (轻微克制) */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-subtle: 0 2px 10px rgba(29, 40, 45, 0.04);
  --shadow-hover: 0 4px 16px rgba(29, 40, 45, 0.08);
  
  /* 过渡 */
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
}

/* --- 2. 基础重置 --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--text-body);
  background-color: var(--bg-main);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img, svg {
  display: inline-block;
  vertical-align: middle;
  max-width: 100%;
}

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

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

ul, ol {
  list-style: none;
}

table {
  border-collapse: collapse;
  width: 100%;
}

/* --- 3. 布局容器 --- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

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

/* --- 4. 标题与排版 --- */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.35;
}

h1 {
  font-size: clamp(32px, 4.5vw, 50px);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(24px, 3vw, 34px);
  letter-spacing: -0.01em;
}

h3 {
  font-size: 22px;
}

h4 {
  font-size: 18px;
}

p {
  margin-bottom: 1.25em;
}

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

.text-main { color: var(--text-main); }
.text-body { color: var(--text-body); }
.text-muted { color: var(--text-muted); }

/* 章节标签 (如 01 / 设备分流) */
.section-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--color-river-blue);
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-badge::before {
  content: "";
  display: inline-block;
  width: 18px;
  height: 2px;
  background-color: var(--color-river-blue);
}

.section-header {
  margin-bottom: 40px;
}

.section-header p {
  margin-top: 12px;
  font-size: 17px;
  color: var(--text-body);
  max-width: 780px;
}

/* --- 5. 按钮与交互 --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  text-align: center;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

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

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

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

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

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

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

.btn-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--color-river-blue);
  font-size: 14px;
  font-weight: 600;
  padding: 4px 0;
  border-bottom: 1px solid transparent;
}

.btn-link:hover {
  color: var(--color-deep-blue);
  border-bottom-color: var(--color-deep-blue);
}

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

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

/* --- 6. 导航栏 Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--color-border);
}

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

.brand-group {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.brand-logo-svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

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

.brand-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.1;
  letter-spacing: -0.01em;
}

.brand-subline {
  font-size: 11px;
  color: var(--text-muted);
  letter-spacing: 0.02em;
  margin-top: 2px;
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 18px;
}

.nav-link {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-body);
  padding: 8px 2px;
  position: relative;
  transition: color var(--transition-fast);
}

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

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

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-river-blue);
}

.header-cta-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
  color: var(--text-main);
}

.mobile-menu-btn svg {
  width: 24px;
  height: 24px;
}

/* 移动端抽屉导航 */
.mobile-drawer {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-white);
  border-top: 1px solid var(--color-border);
  padding: 24px;
  overflow-y: auto;
  z-index: 99;
}

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

.mobile-nav-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 24px;
}

.mobile-nav-item a {
  display: block;
  font-size: 16px;
  font-weight: 500;
  color: var(--text-main);
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-main);
}

.mobile-nav-item a:hover {
  background-color: var(--bg-light-blue);
  color: var(--color-deep-blue);
}

/* --- 7. Hero 信息流入口 --- */
.hero-section {
  position: relative;
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--color-border);
  padding-top: 54px;
  padding-bottom: 60px;
}

.hero-header-block {
  max-width: 860px;
  margin-bottom: 44px;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-light-blue);
  color: var(--color-river-blue);
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 18px;
  border: 1px solid rgba(68, 107, 120, 0.15);
}

.hero-h1 {
  font-size: clamp(30px, 3.8vw, 46px);
  color: var(--text-main);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
  font-weight: 700;
}

.hero-lead {
  font-size: clamp(20px, 2.2vw, 26px);
  color: var(--color-deep-blue);
  font-weight: 600;
  line-height: 1.45;
  margin-bottom: 10px;
}

.hero-subhead {
  font-size: 15px;
  color: var(--color-deep-cyan);
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-bottom: 16px;
}

.hero-body-text {
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.8;
  max-width: 780px;
  margin-bottom: 24px;
}

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

/* Hero 四条信息流展示 (自然分流带) */
.hero-stream-block {
  margin-top: 36px;
  padding-top: 32px;
  border-top: 1px dashed var(--color-border);
}

.stream-label-sub {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.stream-label-sub::after {
  content: "";
  flex: 1;
  height: 1px;
  background-color: var(--color-border-subtle);
}

.stream-flow-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* 4 条长短不一的流线横带，形成自然分流感 */
.stream-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  background-color: var(--bg-main);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-river-blue);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.stream-band:hover {
  background-color: #FFFFFF;
  border-color: var(--color-river-blue);
  box-shadow: var(--shadow-subtle);
}

/* 不等宽错落感 */
.stream-band-1 { width: 100%; border-left-color: var(--color-river-blue); }
.stream-band-2 { width: 94%; border-left-color: var(--color-deep-cyan); }
.stream-band-3 { width: 97%; border-left-color: var(--color-deep-blue); }
.stream-band-4 { width: 91%; border-left-color: var(--color-terracotta); }

.stream-band-left {
  display: flex;
  align-items: center;
  gap: 16px;
  min-width: 110px;
}

.stream-node-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-river-blue);
  flex-shrink: 0;
}

.stream-band-2 .stream-node-dot { background-color: var(--color-deep-cyan); }
.stream-band-3 .stream-node-dot { background-color: var(--color-deep-blue); }
.stream-band-4 .stream-node-dot { background-color: var(--color-terracotta); }

.stream-band-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.stream-band-mid {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  flex: 1;
  padding: 0 20px;
}

.stream-tag-item {
  font-size: 13px;
  color: var(--text-body);
  background-color: #FFFFFF;
  padding: 3px 10px;
  border-radius: 2px;
  border: 1px solid var(--color-border-subtle);
}

.stream-band-right {
  flex-shrink: 0;
}

.stream-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-river-blue);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.stream-band:hover .stream-link {
  color: var(--color-deep-blue);
}

/* --- 8. 模块通用区段 --- */
.site-section {
  padding-top: 72px;
  padding-bottom: 72px;
  border-bottom: 1px solid var(--color-border);
}

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

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

/* --- 9. 01 / 设备分流表 --- */
.flow-table-wrap {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--bg-white);
  overflow: hidden;
}

.flow-table-row {
  display: grid;
  grid-template-columns: 140px 1.4fr 1.6fr 130px;
  align-items: center;
  padding: 20px 24px;
  border-bottom: 1px solid var(--color-border-subtle);
  transition: background-color var(--transition-fast);
}

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

.flow-table-row:hover {
  background-color: var(--bg-light-blue);
}

.flow-table-head {
  background-color: var(--bg-main);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.04em;
  padding: 12px 24px;
}

.flow-table-head:hover {
  background-color: var(--bg-main);
}

.flow-col-device {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 10px;
}

.flow-col-purpose {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.6;
}

.flow-col-detail {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
  padding-right: 16px;
}

.flow-col-action {
  text-align: right;
}

/* --- 10. 02 / 使用场景纵向分流清单 --- */
.vertical-flow-list {
  display: flex;
  flex-direction: column;
  position: relative;
}

/* 纵向信息流主导线 */
.vertical-flow-list::before {
  content: "";
  position: absolute;
  top: 24px;
  bottom: 24px;
  left: 27px;
  width: 2px;
  background-color: var(--color-border);
}

.vertical-flow-item {
  display: flex;
  align-items: flex-start;
  gap: 24px;
  padding: 22px 0;
  position: relative;
}

.flow-node-index {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-sm);
  background-color: #FFFFFF;
  border: 2px solid var(--color-river-blue);
  color: var(--color-deep-blue);
  font-size: 16px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  z-index: 1;
}

.vertical-flow-item:nth-child(even) .flow-node-index {
  border-color: var(--color-deep-cyan);
}

.flow-node-content {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
  flex: 1;
  display: grid;
  grid-template-columns: 200px 1fr 140px;
  align-items: center;
  gap: 20px;
  transition: all var(--transition-fast);
}

.vertical-flow-item:hover .flow-node-content {
  border-color: var(--color-river-blue);
  box-shadow: var(--shadow-subtle);
}

.flow-node-title h3 {
  font-size: 18px;
  margin-bottom: 4px;
}

.flow-node-title span {
  font-size: 12px;
  color: var(--text-muted);
}

.flow-node-desc {
  font-size: 14px;
  color: var(--text-body);
}

.flow-node-desc strong {
  color: var(--color-deep-blue);
  font-weight: 600;
}

/* --- 11. 03 / AI 工具分流索引 --- */
.ai-stream-index {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.ai-index-row {
  display: grid;
  grid-template-columns: 180px 1.4fr 1.2fr 130px;
  align-items: center;
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 18px 24px;
  transition: all var(--transition-fast);
}

.ai-index-row:hover {
  border-color: var(--color-deep-cyan);
  box-shadow: var(--shadow-subtle);
}

.ai-tool-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.ai-tool-name::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-deep-cyan);
}

.ai-factor-text {
  font-size: 14px;
  color: var(--text-body);
}

.ai-factor-text strong {
  color: var(--color-deep-blue);
  font-weight: 600;
}

.ai-direction-text {
  font-size: 13px;
  color: var(--text-muted);
}

/* 说明小提示框 */
.note-box {
  margin-top: 24px;
  padding: 16px 20px;
  background-color: var(--bg-light-blue);
  border-left: 3px solid var(--color-river-blue);
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.7;
}

/* --- 12. 04 / 流媒体分流行 --- */
.streaming-stream-wrap {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.streaming-row {
  display: grid;
  grid-template-columns: 160px 1.3fr 1.3fr 130px;
  align-items: center;
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 18px 24px;
  transition: all var(--transition-fast);
}

.streaming-row:hover {
  border-color: var(--color-river-blue);
  box-shadow: var(--shadow-subtle);
}

.streaming-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.streaming-name::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-river-blue);
}

.streaming-col {
  font-size: 14px;
  color: var(--text-body);
}

/* --- 13. 05 / 节点地区支流索引 --- */
.region-stream-index {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.region-branch-row {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 22px 26px;
  display: grid;
  grid-template-columns: 140px 1.4fr 1.3fr 130px;
  align-items: center;
  gap: 16px;
  transition: all var(--transition-fast);
}

.region-branch-row:hover {
  border-color: var(--color-deep-blue);
  box-shadow: var(--shadow-subtle);
}

.region-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--color-deep-blue);
  display: flex;
  align-items: center;
  gap: 10px;
}

.region-title-tag {
  font-size: 11px;
  padding: 2px 6px;
  background-color: var(--bg-light-blue);
  color: var(--color-river-blue);
  border-radius: 2px;
  font-weight: 600;
}

.region-desc {
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.7;
}

.region-notice {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.6;
}

/* --- 14. 06 / 线路分流说明表 --- */
.line-table-container {
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background-color: var(--bg-white);
}

.line-explain-table {
  width: 100%;
  min-width: 680px;
}

.line-explain-table th {
  background-color: var(--bg-main);
  text-align: left;
  padding: 16px 20px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  border-bottom: 1px solid var(--color-border);
  letter-spacing: 0.04em;
}

.line-explain-table td {
  padding: 18px 20px;
  border-bottom: 1px solid var(--color-border-subtle);
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.7;
}

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

.line-explain-table tr:hover td {
  background-color: var(--bg-light-blue);
}

.line-name {
  font-weight: 700;
  color: var(--color-deep-blue);
  font-size: 15px;
}

/* --- 15. 07 / 客户端配置分流 --- */
.client-stream-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.client-stream-row {
  display: grid;
  grid-template-columns: 140px 1.4fr 1.4fr 130px;
  align-items: center;
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 18px 24px;
  transition: all var(--transition-fast);
}

.client-stream-row:hover {
  border-color: var(--color-river-blue);
  box-shadow: var(--shadow-subtle);
}

.client-device-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-main);
}

/* --- 16. 08 / 套餐选择 (核心连续流量带) --- */
.pricing-section {
  background-color: var(--bg-white);
  border-bottom: 1px solid var(--color-border);
  padding-top: 72px;
  padding-bottom: 72px;
}

/* 连续流量带 (Continuous Stream Band) */
.stream-pricing-wrapper {
  margin-top: 40px;
  position: relative;
}

/* 2px 主线 */
.stream-flow-line {
  position: absolute;
  top: 36px;
  left: 60px;
  right: 60px;
  height: 2px;
  background-color: var(--color-line);
  z-index: 0;
}

.stream-pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  position: relative;
  z-index: 1;
}

.pricing-node-card {
  background-color: #FFFFFF;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  position: relative;
  transition: all var(--transition-fast);
}

.pricing-node-card:hover {
  border-color: var(--color-river-blue);
  box-shadow: var(--shadow-subtle);
}

/* 流量节点指示圆 */
.pricing-flow-dot {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background-color: #FFFFFF;
  border: 2px solid var(--color-river-blue);
  color: var(--color-river-blue);
  font-size: 10px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.pricing-tier-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 8px;
}

.pricing-traffic-badge {
  font-size: 20px;
  font-weight: 800;
  color: var(--color-deep-blue);
  letter-spacing: -0.01em;
  margin-bottom: 8px;
}

.pricing-price-text {
  font-size: 24px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
}

.pricing-price-unit {
  font-size: 13px;
  font-weight: 400;
  color: var(--text-muted);
}

.pricing-suit-text {
  font-size: 13px;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 20px;
  flex: 1;
}

.pricing-card-btn {
  width: 100%;
}

/* 主流方案：唯一重点突出 (350GB 节点) */
.pricing-node-card.featured {
  background-color: var(--bg-light-green);
  border: 2px solid var(--color-deep-cyan);
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}

.pricing-node-card.featured .pricing-flow-dot {
  background-color: var(--color-deep-blue);
  border-color: var(--color-deep-blue);
  color: #FFFFFF;
}

.featured-ribbon {
  position: absolute;
  top: -12px;
  background-color: var(--color-terracotta);
  color: #FFFFFF;
  font-size: 11px;
  font-weight: 700;
  padding: 3px 12px;
  border-radius: 20px;
  letter-spacing: 0.04em;
}

/* 长期方案：单独下方展示 */
.longterm-plan-bar {
  margin-top: 32px;
  background-color: var(--bg-main);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-river-blue);
  border-radius: var(--radius-sm);
  padding: 20px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.longterm-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.longterm-tag {
  background-color: var(--color-river-blue);
  color: #FFFFFF;
  font-size: 12px;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
}

.longterm-title {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-main);
}

.longterm-mid {
  font-size: 14px;
  color: var(--text-body);
}

.longterm-mid strong {
  color: var(--color-deep-blue);
  font-size: 18px;
}

/* 快速选择路径 */
.quick-pick-guide {
  margin-top: 28px;
  padding: 18px 24px;
  background-color: #FFFFFF;
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13px;
  color: var(--text-body);
}

.quick-pick-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.quick-pick-item span {
  color: var(--text-muted);
}

.quick-pick-item strong {
  color: var(--color-deep-blue);
}

/* --- 17. 09 / River VPN深度评测精要 --- */
.review-lead-box {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 32px;
  display: grid;
  grid-template-columns: 1.8fr 1fr;
  gap: 36px;
  align-items: center;
}

.review-lead-info h3 {
  font-size: 22px;
  margin-bottom: 14px;
}

.review-lead-info p {
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-body);
  margin-bottom: 20px;
}

.review-points-list {
  background-color: var(--bg-main);
  border-left: 3px solid var(--color-deep-cyan);
  padding: 20px;
  border-radius: var(--radius-sm);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.review-point-item {
  font-size: 13px;
  color: var(--text-body);
  display: flex;
  align-items: flex-start;
  gap: 8px;
}

.review-point-item::before {
  content: "•";
  color: var(--color-deep-cyan);
  font-size: 16px;
  line-height: 1;
}

/* --- 18. 10 / 内容分流区 (9篇文章分流) --- */
.content-stream-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.content-stream-branch {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 24px;
  display: flex;
  flex-direction: column;
}

.branch-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 16px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--color-border-subtle);
}

.branch-title-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.branch-title-wrap h3 {
  font-size: 18px;
  color: var(--text-main);
}

.branch-badge {
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  background-color: var(--bg-light-blue);
  color: var(--color-river-blue);
  border-radius: 2px;
}

.branch-articles-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.article-stream-row {
  display: flex;
  flex-direction: column;
  padding-bottom: 14px;
  border-bottom: 1px dashed var(--color-border-subtle);
  transition: all var(--transition-fast);
}

.article-stream-row:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.article-row-meta {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 4px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.article-row-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.5;
  margin-bottom: 6px;
}

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

.article-row-excerpt {
  font-size: 13px;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 8px;
}

/* --- 19. 11 / 网络排障故障分流 --- */
.troubleshooting-flow {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.symptom-branch-block {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 24px;
}

.symptom-branch-block h3 {
  font-size: 18px;
  margin-bottom: 16px;
  color: var(--text-main);
}

.symptom-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.symptom-card {
  background-color: var(--bg-main);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.symptom-card strong {
  font-size: 14px;
  color: var(--color-deep-blue);
}

.symptom-card p {
  font-size: 12px;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 0;
}

.trouble-steps-container {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 28px;
}

.trouble-steps-container h3 {
  font-size: 18px;
  margin-bottom: 20px;
}

.trouble-steps-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.trouble-step-item {
  background-color: var(--bg-main);
  border-radius: var(--radius-sm);
  padding: 16px;
  border-top: 3px solid var(--color-river-blue);
}

.trouble-step-num {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-river-blue);
  margin-bottom: 4px;
}

.trouble-step-name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 6px;
}

.trouble-step-detail {
  font-size: 12px;
  color: var(--text-body);
  line-height: 1.6;
}

/* --- 20. 12 / 常见问题 (FAQ 分流问答) --- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

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

.faq-item[open] {
  border-color: var(--color-river-blue);
}

.faq-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  cursor: pointer;
  user-select: none;
  list-style: none;
}

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-summary-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.faq-q-num {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-river-blue);
  background-color: var(--bg-light-blue);
  padding: 3px 8px;
  border-radius: 2px;
}

.faq-question-text {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-main);
}

.faq-icon-plus {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
}

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

.faq-answer {
  padding: 0 24px 20px 58px;
  font-size: 14px;
  color: var(--text-body);
  line-height: 1.8;
  border-top: 1px dashed var(--color-border-subtle);
  padding-top: 16px;
}

/* --- 21. 文章页面样式 (Article Template) --- */
.article-page-wrap {
  padding-top: 40px;
  padding-bottom: 72px;
}

.article-breadcrumbs {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

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

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

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

.article-paper {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 40px 48px;
}

.article-header {
  border-bottom: 1px solid var(--color-border-subtle);
  padding-bottom: 28px;
  margin-bottom: 32px;
}

.article-category-badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-light-blue);
  color: var(--color-river-blue);
  margin-bottom: 14px;
}

.article-h1 {
  font-size: clamp(26px, 3.2vw, 36px);
  color: var(--text-main);
  line-height: 1.4;
  margin-bottom: 16px;
}

.article-lead-abstract {
  font-size: 16px;
  color: var(--text-body);
  line-height: 1.8;
  margin-bottom: 20px;
}

.article-meta-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 13px;
  color: var(--text-muted);
}

/* GEO 快速结论框 (Fast Conclusion for GEO & Readers) */
.geo-fast-conclusion {
  background-color: var(--bg-light-green);
  border: 1px solid #D5E4DF;
  border-left: 4px solid var(--color-deep-cyan);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  margin-bottom: 32px;
}

.geo-fast-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-deep-green);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.geo-fast-conclusion p {
  font-size: 14px;
  color: var(--text-main);
  line-height: 1.7;
  margin-bottom: 0;
}

/* 目录 (TOC) */
.article-toc {
  background-color: var(--bg-main);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
  margin-bottom: 36px;
}

.article-toc-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 12px;
}

.article-toc ul {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.article-toc li {
  font-size: 14px;
  line-height: 1.5;
}

.article-toc a {
  color: var(--color-river-blue);
}

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

/* 文章正文排版 */
.article-content {
  font-size: 16px;
  line-height: 1.85;
  color: var(--text-body);
}

.article-content h2 {
  font-size: 24px;
  margin-top: 40px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border-subtle);
  color: var(--text-main);
}

.article-content h3 {
  font-size: 19px;
  margin-top: 28px;
  margin-bottom: 12px;
  color: var(--color-deep-blue);
}

.article-content p {
  margin-bottom: 1.4em;
}

.article-content ul, .article-content ol {
  margin-bottom: 1.4em;
  padding-left: 24px;
}

.article-content ul {
  list-style: disc;
}

.article-content ol {
  list-style: decimal;
}

.article-content li {
  margin-bottom: 0.6em;
}

.article-content strong {
  color: var(--text-main);
  font-weight: 600;
}

.article-content table {
  margin-bottom: 2em;
  font-size: 14px;
  border: 1px solid var(--color-border);
}

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

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

/* 文章商业 CTA 插入卡 */
.article-cta-box {
  margin: 40px 0;
  background-color: var(--bg-light-blue);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-terracotta);
  border-radius: var(--radius-sm);
  padding: 24px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.article-cta-info h4 {
  font-size: 17px;
  margin-bottom: 6px;
  color: var(--text-main);
}

.article-cta-info p {
  font-size: 13px;
  color: var(--text-body);
  margin-bottom: 0;
}

/* 底部内链导航 (闭环) */
.article-footer-nav {
  margin-top: 48px;
  padding-top: 28px;
  border-top: 1px solid var(--color-border-subtle);
}

.article-related-box {
  margin-bottom: 32px;
}

.article-related-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
}

.article-related-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.article-related-link-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-river-blue);
}

.article-related-link-item::before {
  content: "→";
  color: var(--color-river-blue);
}

.article-related-link-item:hover {
  color: var(--color-deep-blue);
  text-decoration: underline;
}

.prev-next-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.prev-next-card {
  background-color: var(--bg-main);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.prev-next-card span {
  font-size: 12px;
  color: var(--text-muted);
}

.prev-next-card strong {
  font-size: 14px;
  color: var(--text-main);
}

.prev-next-card:hover {
  border-color: var(--color-river-blue);
}

/* --- 22. 分类页面 (Category Template) --- */
.category-header-box {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 36px 40px;
  margin-bottom: 32px;
}

.category-h1 {
  font-size: clamp(26px, 3.2vw, 36px);
  margin-bottom: 12px;
}

.category-desc {
  font-size: 15px;
  color: var(--text-body);
  line-height: 1.8;
  max-width: 800px;
  margin-bottom: 0;
}

/* --- 23. 页脚 Footer --- */
.site-footer {
  margin-top: auto;
  background-color: var(--color-footer-bg);
  border-top: 1px solid var(--color-border);
  color: var(--color-footer-text);
  padding-top: 48px;
  padding-bottom: 32px;
}

.footer-top-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr 1.2fr;
  gap: 32px;
  padding-bottom: 36px;
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.footer-col-brand .brand-group {
  margin-bottom: 12px;
}

.footer-desc {
  font-size: 13px;
  line-height: 1.7;
  color: var(--color-footer-text);
  margin-bottom: 16px;
}

.footer-col-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}

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

.footer-links-list a {
  font-size: 13px;
  color: var(--color-footer-text);
}

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

/* 页脚底部固定两端对齐 */
.footer-bottom-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  font-size: 12px;
  flex-wrap: wrap;
  gap: 16px;
}

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

.footer-friendly-links {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

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

.friendly-item a {
  color: var(--color-footer-text);
  text-decoration: none;
}

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

/* --- 24. 404 / 静态信息页面 --- */
.static-page-box {
  background-color: var(--bg-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 48px;
  margin: 40px auto;
  max-width: 820px;
}

.error-404-wrap {
  text-align: center;
  padding: 60px 20px;
}

.error-code {
  font-size: 72px;
  font-weight: 800;
  color: var(--color-river-blue);
  line-height: 1;
  margin-bottom: 16px;
}

.error-title {
  font-size: 22px;
  margin-bottom: 12px;
}

.error-desc {
  font-size: 15px;
  color: var(--text-body);
  margin-bottom: 28px;
}

.error-links-grid {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

/* --- 25. 响应式适配 --- */

/* 1024px 及以下 (Tablet / Laptop) */
@media (max-width: 1024px) {
  .desktop-nav {
    display: none;
  }
  
  .mobile-menu-btn {
    display: flex;
  }
  
  .footer-top-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .stream-pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .stream-flow-line {
    display: none;
  }
  
  .pricing-node-card.featured {
    transform: none;
  }
  
  .content-stream-grid {
    grid-template-columns: 1fr;
  }
  
  .trouble-steps-list {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .symptom-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* 768px 及以下 (Tablet Portrait / Mobile) */
@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  
  .hero-section {
    padding-top: 36px;
    padding-bottom: 44px;
  }
  
  .site-section {
    padding-top: 50px;
    padding-bottom: 50px;
  }
  
  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }
  
  .hero-actions .btn {
    width: 100%;
  }
  
  /* Hero 信息流转为移动端垂直流 */
  .stream-band {
    width: 100% !important;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  
  .stream-band-mid {
    padding: 0;
    width: 100%;
  }
  
  .stream-band-right {
    width: 100%;
    display: flex;
    justify-content: flex-end;
  }
  
  /* 设备分流表移动端自适应 */
  .flow-table-head {
    display: none;
  }
  
  .flow-table-row {
    grid-template-columns: 1fr;
    gap: 8px;
    padding: 16px 20px;
  }
  
  .flow-col-action {
    text-align: left;
    margin-top: 4px;
  }
  
  /* 场景纵向清单 */
  .vertical-flow-list::before {
    left: 20px;
  }
  
  .flow-node-index {
    width: 42px;
    height: 42px;
    font-size: 14px;
  }
  
  .flow-node-content {
    grid-template-columns: 1fr;
    gap: 12px;
    padding: 16px;
  }
  
  /* AI 工具 & 流媒体 & 节点移动端单列 */
  .ai-index-row,
  .streaming-row,
  .region-branch-row,
  .client-stream-row {
    grid-template-columns: 1fr;
    gap: 10px;
    padding: 16px 20px;
  }
  
  .review-lead-box {
    grid-template-columns: 1fr;
    padding: 24px;
  }
  
  .trouble-steps-list,
  .symptom-grid {
    grid-template-columns: 1fr;
  }
  
  .article-paper {
    padding: 24px 20px;
  }
  
  .prev-next-nav {
    grid-template-columns: 1fr;
  }
  
  .footer-top-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  
  .footer-bottom-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
}

/* 430px / 390px / 375px 小屏手机严格适配 */
@media (max-width: 480px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
  
  .brand-subline {
    display: none;
  }
  
  /* 移动端套餐按要求顺序展示：主流 -> 日常 -> 轻量 -> 高流量 -> 长期 */
  .stream-pricing-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
  }
  
  .pricing-node-card.card-featured { order: 1; }
  .pricing-node-card.card-daily { order: 2; }
  .pricing-node-card.card-light { order: 3; }
  .pricing-node-card.card-heavy { order: 4; }
  
  .longterm-plan-bar {
    flex-direction: column;
    align-items: flex-start;
    padding: 20px;
  }
  
  .longterm-left {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
  
  .longterm-plan-bar .btn {
    width: 100%;
  }
  
  .quick-pick-guide {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .faq-summary {
    padding: 16px;
  }
  
  .faq-answer {
    padding: 12px 16px 16px 16px;
  }
}

/* --- 26. 无障碍与动效偏好 (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;
  }
}