/* ==========================================================================
   咸鱼加速器 (XianYu Accelerator) - 官方网站样式系统
   设计理念：日式极简美学 (Japanese Minimalism) · 克制排版 · 自然纸色 · 安静留白 · 细腻微交互
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. 基础重置与设计令牌 (CSS Custom Properties)
   -------------------------------------------------------------------------- */
:root {
  /* 品牌色与自然色彩 (Natural Color Palette) */
  --bg-canvas: #FAF9F5;         /* 温润和纸米白底色 */
  --bg-surface: #FFFFFF;        /* 纯净卡片表面 */
  --bg-subtle: #F3F0E9;         /* 亚麻质感微灰 */
  --bg-elevated: #FFFFFF;
  --bg-dark: #1A1F26;           /* 深色页脚/对比色 */
  
  /* 墨色系文本 (Sumi Ink Scale) */
  --text-primary: #1F2429;      /* 浓墨：正文与主标题 */
  --text-secondary: #586069;    /* 中灰：副标题与辅助说明 */
  --text-tertiary: #8A9199;     /* 淡灰：注脚与元数据 */
  --text-inverse: #FFFFFF;
  
  /* 强调色与点缀 (Natural Accents) */
  --accent-ink: #1E2D3D;        /* 日式深绀蓝：主按钮与重点 */
  --accent-terracotta: #D35C37; /* 柿漆暖橙：活动与特惠推荐标 */
  --accent-matcha: #2E6B56;     /* 抹茶竹青：在线节点与高可靠状态 */
  --accent-soft-orange: #FAF0EB;/* 暖橙微浅背景 */
  --accent-soft-blue: #EFF4F9;  /* 浅绀蓝背景 */

  /* 边框与阴影 (Refined Borders & Quiet Shadows) */
  --border-light: #E7E3D8;
  --border-subtle: rgba(30, 36, 44, 0.08);
  --border-focus: #1E2D3D;
  --shadow-sm: 0 2px 6px rgba(34, 30, 24, 0.03);
  --shadow-md: 0 8px 24px rgba(34, 30, 24, 0.05);
  --shadow-lg: 0 16px 40px rgba(34, 30, 24, 0.08);
  --shadow-card-hover: 0 12px 32px rgba(30, 45, 61, 0.09);

  /* 字体栈 (粗圆与人文无衬线优先) */
  --font-round: ui-rounded, "Hiragino Maru Gothic ProN", "Yu Gothic UI", "PingFang SC", "Microsoft YaHei", "YouYuan", "幼圆", sans-serif;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", Consolas, monospace;

  /* 间距与圆角 */
  --radius-xs: 4px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-pill: 9999px;
  
  --container-max: 1140px;
  --header-height: 72px;
  --transition-smooth: all 0.25s cubic-bezier(0.2, 0.8, 0.2, 1);
}

/* 全局重置 */
*, *::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-body);
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  line-height: 1.7;
  font-weight: 400;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

img, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition-smooth);
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
  border: none;
  background: none;
}

button {
  cursor: pointer;
}

/* 键盘可访问性焦点反馈 */
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--accent-ink);
  outline-offset: 3px;
  border-radius: var(--radius-xs);
}

/* 尊重减弱动态效果 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto !important;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* --------------------------------------------------------------------------
   2. 布局骨架与通用工具类
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

.section {
  padding-top: 84px;
  padding-bottom: 84px;
  position: relative;
}

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

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 52px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8125rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-terracotta);
  background: var(--accent-soft-orange);
  padding: 4px 14px;
  border-radius: var(--radius-pill);
  font-weight: 600;
  margin-bottom: 12px;
}

.section-title {
  font-family: var(--font-round);
  font-size: 2.125rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 14px;
  letter-spacing: -0.01em;
}

.section-desc {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* 标题粗圆体专用风格类 */
.brand-round-font {
  font-family: var(--font-round);
  font-weight: 700;
  letter-spacing: -0.02em;
}

/* --------------------------------------------------------------------------
   3. 按钮系统 (Buttons)
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-pill);
  transition: var(--transition-smooth);
  white-space: nowrap;
  line-height: 1.3;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--accent-ink);
  color: #FFFFFF;
  box-shadow: 0 4px 14px rgba(30, 45, 61, 0.18);
}

.btn-primary:hover {
  background-color: #2D3F54;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(30, 45, 61, 0.25);
  color: #FFFFFF;
}

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

.btn-accent {
  background-color: var(--accent-terracotta);
  color: #FFFFFF;
  box-shadow: 0 4px 14px rgba(211, 92, 55, 0.22);
}

.btn-accent:hover {
  background-color: #BE4F2B;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(211, 92, 55, 0.3);
  color: #FFFFFF;
}

.btn-secondary {
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  background-color: var(--bg-subtle);
  border-color: #D4CEBE;
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 18px;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 15px 34px;
  font-size: 1.0625rem;
}

/* --------------------------------------------------------------------------
   4. 页眉导航 (Header & Navigation)
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(250, 249, 245, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  height: var(--header-height);
  transition: background-color 0.3s ease;
}

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

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

.logo-img {
  width: 38px;
  height: 38px;
}

.logo-text {
  font-family: var(--font-round);
  font-size: 1.3125rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.logo-badge {
  font-size: 0.6875rem;
  font-family: var(--font-body);
  font-weight: 500;
  color: var(--accent-terracotta);
  background: var(--accent-soft-orange);
  padding: 2px 7px;
  border-radius: var(--radius-pill);
}

.nav-links {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 32px;
}

.nav-link {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  font-weight: 500;
  position: relative;
  padding: 6px 0;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-ink);
  transition: width 0.2s ease;
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

.nav-link--highlight {
  color: var(--accent-terracotta);
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 移动端汉堡菜单按钮 */
.mobile-nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  border-radius: var(--radius-sm);
  background: transparent;
}

.mobile-nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.mobile-nav-toggle.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.mobile-nav-toggle.open span:nth-child(2) {
  opacity: 0;
}
.mobile-nav-toggle.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   5. 主视觉首屏 (Hero Section)
   桌面端文案与动态图卡错落排列，手机端上下排列
   -------------------------------------------------------------------------- */
.hero-section {
  padding-top: 60px;
  padding-bottom: 80px;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
}

.hero-content {
  max-width: 620px;
}

.hero-pill-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background-color: #FFFFFF;
  border: 1px solid var(--border-light);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  font-size: 0.84375rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.status-dot {
  width: 8px;
  height: 8px;
  background-color: var(--accent-matcha);
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 0 3px rgba(46, 107, 86, 0.2);
}

.hero-title {
  font-family: var(--font-round);
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.18;
  color: var(--text-primary);
  letter-spacing: -0.025em;
  margin-bottom: 20px;
}

.hero-title .title-accent {
  color: var(--accent-terracotta);
  display: inline-block;
}

.hero-subtitle {
  font-size: 1.1875rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 34px;
  max-width: 540px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  margin-bottom: 36px;
}

.hero-meta-badges {
  display: flex;
  align-items: center;
  gap: 24px;
  padding-top: 18px;
  border-top: 1px solid var(--border-light);
}

.meta-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.meta-item svg {
  width: 16px;
  height: 16px;
  color: var(--accent-matcha);
}

/* 主视觉右侧：错落自然排布的动态卡片组合 */
.hero-visual-board {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.staggered-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 22px;
  box-shadow: var(--shadow-md);
  transition: var(--transition-smooth);
}

.staggered-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
}

.card-stagger-1 {
  margin-left: 0;
  max-width: 95%;
  border-left: 4px solid var(--accent-terracotta);
}

.card-stagger-2 {
  margin-left: auto;
  width: 90%;
  border-left: 4px solid var(--accent-matcha);
}

.card-stagger-3 {
  margin-left: 10px;
  max-width: 88%;
  border-left: 4px solid var(--accent-ink);
}

.card-header-flex {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}

.card-title-sm {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.badge-ping {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
  background: #E8F5E9;
  color: #2E7D32;
}

.node-speed-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.84375rem;
  margin-top: 8px;
  color: var(--text-secondary);
}

.node-progress-track {
  width: 100%;
  height: 5px;
  background: var(--bg-subtle);
  border-radius: 99px;
  overflow: hidden;
  margin-top: 6px;
}

.node-progress-fill {
  height: 100%;
  border-radius: 99px;
  background: linear-gradient(90deg, #2E6B56, #52B788);
}

.protocol-tag-list {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 10px;
}

.protocol-badge {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  padding: 3px 9px;
  border-radius: var(--radius-xs);
  color: var(--text-secondary);
}

/* --------------------------------------------------------------------------
   6. 核心优势卡片 (Core Advantages)
   -------------------------------------------------------------------------- */
.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.advantage-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 34px 28px;
  transition: var(--transition-smooth);
  display: flex;
  flex-direction: column;
}

.advantage-card:hover {
  transform: translateY(-5px);
  border-color: #D3CEBF;
  box-shadow: var(--shadow-card-hover);
}

.card-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--bg-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-ink);
  margin-bottom: 22px;
}

.card-icon-box svg {
  width: 26px;
  height: 26px;
}

.advantage-card h3 {
  font-family: var(--font-round);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.advantage-card p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* --------------------------------------------------------------------------
   7. 流媒体与 AI 支持 (Streaming & AI Section)
   -------------------------------------------------------------------------- */
.stream-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 36px;
}

.stream-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 22px 18px;
  text-align: center;
  transition: var(--transition-smooth);
}

.stream-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: #CDC7B6;
}

.stream-icon {
  width: 44px;
  height: 44px;
  margin: 0 auto 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.stream-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.stream-status {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.stream-notice-box {
  background: #FFFFFF;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  max-width: 860px;
  margin: 0 auto;
}

.notice-icon {
  color: var(--accent-terracotta);
  flex-shrink: 0;
  margin-top: 2px;
}

.stream-notice-box p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   8. 套餐对比 (Pricing Comparison)
   -------------------------------------------------------------------------- */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 34px 26px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition-smooth);
}

.pricing-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card-hover);
}

.pricing-card--popular {
  border: 2px solid var(--accent-ink);
  box-shadow: var(--shadow-md);
}

.popular-badge {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent-ink);
  color: #FFFFFF;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 3px 14px;
  border-radius: var(--radius-pill);
}

.plan-title {
  font-family: var(--font-round);
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.plan-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 22px;
  min-height: 42px;
}

.plan-price-box {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 24px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--border-light);
}

.price-currency {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.price-amount {
  font-family: var(--font-round);
  font-size: 2.75rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
}

.price-period {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.plan-features {
  list-style: none;
  margin-bottom: 28px;
  flex-grow: 1;
}

.plan-feature-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.5;
}

.plan-feature-item svg {
  width: 16px;
  height: 16px;
  color: var(--accent-matcha);
  flex-shrink: 0;
  margin-top: 3px;
}

.pricing-notes {
  margin-top: 32px;
  text-align: center;
  font-size: 0.84375rem;
  color: var(--text-tertiary);
}

/* --------------------------------------------------------------------------
   9. 用户评价模块 (Reviews - 按需求要求默认隐藏并在交付中说明)
   -------------------------------------------------------------------------- */
#reviews-section {
  display: none; /* 按指令要求：无真实已核实资料时不编造，先隐藏该模块并在交付说明中列出待补充资料 */
}

/* --------------------------------------------------------------------------
   10. 常见问题 (FAQ Accordion)
   -------------------------------------------------------------------------- */
.faq-container {
  max-width: 820px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  margin-bottom: 14px;
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-item:hover {
  border-color: #D3CEBF;
}

.faq-trigger {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  text-align: left;
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text-primary);
  background: none;
  border: none;
  cursor: pointer;
}

.faq-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  transition: transform 0.25s ease;
  color: var(--text-secondary);
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
}

.faq-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s cubic-bezier(0, 1, 0, 1), padding 0.3s ease;
  padding: 0 24px;
}

.faq-item.active .faq-content {
  max-height: 500px;
  transition: max-height 0.35s cubic-bezier(1, 0, 1, 0), padding 0.3s ease;
  padding: 0 24px 22px;
}

.faq-content p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* --------------------------------------------------------------------------
   11. 页脚 (Footer)
   仅保留 网站地图、关于我们、服务条款、隐私政策 四个入口并在新标签页打开
   -------------------------------------------------------------------------- */
.site-footer {
  background: #171B20;
  color: #E2E4E8;
  padding: 64px 0 40px;
  border-top: 1px solid #282E37;
}

.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding-bottom: 44px;
  border-bottom: 1px solid #2A303A;
  gap: 40px;
}

.footer-brand {
  max-width: 360px;
}

.footer-brand .logo-text {
  color: #FFFFFF;
}

.footer-desc {
  font-size: 0.875rem;
  color: #9299A2;
  margin-top: 14px;
  line-height: 1.65;
}

.footer-nav {
  display: flex;
  gap: 40px;
}

.footer-col-title {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #FFFFFF;
  margin-bottom: 18px;
}

.footer-links-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-link {
  font-size: 0.90625rem;
  color: #9AA1AB;
  transition: color 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.footer-link:hover {
  color: #FFFFFF;
}

.footer-link svg {
  width: 14px;
  height: 14px;
  opacity: 0.6;
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 32px;
  font-size: 0.8125rem;
  color: #7A818C;
}

.footer-disclaimer {
  max-width: 640px;
  line-height: 1.5;
}

/* --------------------------------------------------------------------------
   12. 右侧章节悬浮导航 (Floating Section Arrow Navigator)
   按页面章节顺序移动，根据滚动位置判断目标，边界禁用，不得遮挡移动端内容
   -------------------------------------------------------------------------- */
.section-nav-widget {
  position: fixed;
  right: 28px;
  bottom: 40px;
  z-index: 990;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.section-nav-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: var(--transition-smooth);
}

.section-nav-btn:hover:not(:disabled) {
  background: var(--accent-ink);
  color: #FFFFFF;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(30, 45, 61, 0.2);
}

.section-nav-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
  pointer-events: none;
  background: var(--bg-subtle);
  border-color: var(--border-light);
}

.section-nav-btn svg {
  width: 20px;
  height: 20px;
}

/* --------------------------------------------------------------------------
   13. 独立文章与子页面排版 (Article & Content Page Layout)
   -------------------------------------------------------------------------- */
.article-header {
  padding: 48px 0 32px;
  text-align: center;
  max-width: 820px;
  margin: 0 auto;
}

.article-breadcrumb {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-tertiary);
  margin-bottom: 18px;
}

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

.article-breadcrumb a:hover {
  color: var(--accent-ink);
}

.article-main-title {
  font-family: var(--font-round);
  font-size: 2.375rem;
  font-weight: 800;
  line-height: 1.3;
  color: var(--text-primary);
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.article-body {
  max-width: 820px;
  margin: 0 auto 72px;
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 48px 52px;
  box-shadow: var(--shadow-sm);
  font-size: 1.0625rem;
  line-height: 1.85;
}

.article-body h2 {
  font-family: var(--font-round);
  font-size: 1.625rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 40px;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-light);
}

.article-body h3 {
  font-family: var(--font-round);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 28px;
  margin-bottom: 12px;
}

.article-body p {
  margin-bottom: 20px;
  color: #2F353D;
}

.article-body ul, .article-body ol {
  margin-bottom: 24px;
  padding-left: 24px;
  color: #2F353D;
}

.article-body li {
  margin-bottom: 8px;
}

.article-callout {
  background: var(--bg-subtle);
  border-left: 4px solid var(--accent-ink);
  padding: 18px 22px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 28px 0;
  font-size: 0.9375rem;
}

.article-cta-box {
  background: linear-gradient(135deg, #FAF8F5, #F2EEE5);
  border: 1px solid #DED8CA;
  border-radius: var(--radius-md);
  padding: 28px;
  margin: 36px 0;
  text-align: center;
}

.article-cta-box h4 {
  font-family: var(--font-round);
  font-size: 1.25rem;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.article-cta-box p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-bottom: 18px;
}

/* 知识科普专栏文章列表卡片网格 */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.knowledge-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 30px;
  display: flex;
  flex-direction: column;
  transition: var(--transition-smooth);
}

.knowledge-card:hover {
  transform: translateY(-4px);
  border-color: #D3CEBF;
  box-shadow: var(--shadow-card-hover);
}

.knowledge-card-tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-terracotta);
  background: var(--accent-soft-orange);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  display: inline-block;
  align-self: flex-start;
  margin-bottom: 14px;
}

.knowledge-card-title {
  font-family: var(--font-round);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
  line-height: 1.4;
}

.knowledge-card-summary {
  font-size: 0.90625rem;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 20px;
  flex-grow: 1;
}

.knowledge-card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  border-top: 1px solid var(--border-light);
  padding-top: 14px;
}

/* 网站地图目录列表 */
.sitemap-section-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 32px;
}

.sitemap-group {
  background: var(--bg-surface);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: 28px;
}

.sitemap-group-title {
  font-family: var(--font-round);
  font-size: 1.1875rem;
  font-weight: 700;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--bg-subtle);
  color: var(--text-primary);
}

.sitemap-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.sitemap-links a {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.sitemap-links a:hover {
  color: var(--accent-terracotta);
  transform: translateX(3px);
}

/* --------------------------------------------------------------------------
   14. 响应式适配与移动端优化 (Responsive Design)
   -------------------------------------------------------------------------- */
@media (max-width: 1024px) {
  .advantages-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stream-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .sitemap-section-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  
  .section {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .section-title {
    font-size: 1.75rem;
  }

  /* 移动端主视觉上下排列 */
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .hero-title {
    font-size: 2.25rem;
  }

  .hero-visual-board {
    margin-top: 10px;
  }

  .card-stagger-1, .card-stagger-2, .card-stagger-3 {
    margin-left: 0 !important;
    width: 100% !important;
    max-width: 100% !important;
  }

  /* 移动端导航抽屉 */
  .mobile-nav-toggle {
    display: flex;
  }

  .nav-menu-wrapper {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background: var(--bg-canvas);
    border-top: 1px solid var(--border-light);
    padding: 24px;
    display: none;
    flex-direction: column;
    justify-content: flex-start;
    gap: 20px;
    overflow-y: auto;
  }

  .nav-menu-wrapper.open {
    display: flex;
  }

  .nav-links {
    flex-direction: column;
    align-items: flex-start;
    gap: 18px;
    width: 100%;
  }

  .nav-link {
    font-size: 1.125rem;
    width: 100%;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-light);
  }

  .header-actions {
    width: 100%;
    flex-direction: column;
    margin-top: 16px;
  }

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

  /* 核心单栏排列 */
  .advantages-grid {
    grid-template-columns: 1fr;
  }

  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .knowledge-grid {
    grid-template-columns: 1fr;
  }

  .sitemap-section-list {
    grid-template-columns: 1fr;
  }

  .footer-top {
    flex-direction: column;
  }

  .footer-nav {
    flex-direction: column;
    gap: 24px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 14px;
    text-align: center;
  }

  .article-body {
    padding: 28px 20px;
  }

  .article-main-title {
    font-size: 1.75rem;
  }

  /* 移动端右侧箭头贴右下微调，不遮挡正文与点击区域 */
  .section-nav-widget {
    right: 14px;
    bottom: 24px;
    gap: 8px;
  }

  .section-nav-btn {
    width: 38px;
    height: 38px;
    background: rgba(255, 255, 255, 0.95);
  }
}