/* ==========================================================================
   极速Cloud (JiSu Cloud) - 官方光学极简设计系统 (Photonic Optical Physics)
   风格：建筑极简白 (Architectural White) + 陶瓷白基底 + 棱镜色散光效 + 纯净毛玻璃
   严格禁止：AI星星、魔法棒、卡通机器人；专注光子折射、发丝级微边框与精确实测指标
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. 设计变量与色彩体系 (Design Tokens & Photonic Color Physics)
   -------------------------------------------------------------------------- */
:root {
  /* 陶瓷白极简基底色 */
  --bg-ceramic: #fafafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #ffffff;
  --bg-surface-subtle: #f4f5f8;
  --bg-glass: rgba(255, 255, 255, 0.82);
  --bg-glass-card: rgba(255, 255, 255, 0.65);

  /* 碳素与高对比排版色 */
  --text-charcoal: #121316;
  --text-main: #121316;
  --text-muted: #5c6270;
  --text-subtle: #8a91a0;

  /* 光学专线核心色与色散渐变 */
  --optical-blue: #0969da;
  --optical-blue-hover: #0550ae;
  --optical-cyan: #0891b2;
  --optical-indigo: #4338ca;
  --optical-emerald: #059669;

  /* 棱镜色散高斯微光 (Chromatic Aberration Dispersion) */
  --prism-border-active: linear-gradient(135deg, rgba(239, 68, 68, 0.45) 0%, rgba(245, 158, 11, 0.4) 25%, rgba(16, 185, 129, 0.4) 50%, rgba(6, 182, 212, 0.4) 75%, rgba(99, 102, 241, 0.45) 100%);
  --prism-glow: 0 0 25px rgba(9, 105, 218, 0.12), 0 0 40px rgba(6, 182, 212, 0.08);

  /* 建筑级发丝边框 (Hairline Borders) */
  --border-hairline: rgba(18, 19, 22, 0.07);
  --border-hairline-subtle: rgba(18, 19, 22, 0.04);
  --border-hover: rgba(9, 105, 218, 0.35);

  /* 投影体系 */
  --shadow-subtle: 0 2px 4px rgba(18, 19, 22, 0.02);
  --shadow-card: 0 4px 20px -2px rgba(18, 19, 22, 0.04), 0 2px 6px -1px rgba(18, 19, 22, 0.02);
  --shadow-floating: 0 20px 40px -10px rgba(18, 19, 22, 0.07), 0 8px 16px -4px rgba(18, 19, 22, 0.03);
  --shadow-hover: 0 24px 48px -12px rgba(9, 105, 218, 0.12), 0 8px 18px -4px rgba(18, 19, 22, 0.04);

  --radius-xs: 6px;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --transition-fast: 0.18s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-smooth: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-theme: background 0.4s ease, color 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}

/* 夜间黑曜石模式 (Dark Obsidian Mode) */
[data-theme="dark"] {
  --bg-ceramic: #0b0e14;
  --bg-surface: #12161f;
  --bg-surface-elevated: #171c28;
  --bg-surface-subtle: #151a24;
  --bg-glass: rgba(18, 22, 31, 0.85);
  --bg-glass-card: rgba(23, 28, 40, 0.7);

  --text-charcoal: #f4f6fa;
  --text-main: #f4f6fa;
  --text-muted: #9ba3b5;
  --text-subtle: #6c7587;

  --optical-blue: #38bdf8;
  --optical-blue-hover: #7dd3fc;
  --optical-cyan: #22d3ee;
  --optical-indigo: #818cf8;
  --optical-emerald: #34d399;

  --border-hairline: rgba(255, 255, 255, 0.08);
  --border-hairline-subtle: rgba(255, 255, 255, 0.04);
  --border-hover: rgba(56, 189, 248, 0.4);

  --shadow-subtle: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-card: 0 8px 24px -4px rgba(0, 0, 0, 0.5);
  --shadow-floating: 0 24px 48px -10px rgba(0, 0, 0, 0.7);
  --shadow-hover: 0 24px 48px -10px rgba(56, 189, 248, 0.2);
}

/* --------------------------------------------------------------------------
   2. 基础重置与排版 (Reset & Typography)
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "SF Pro Text", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-ceramic);
  color: var(--text-main);
  line-height: 1.65;
  transition: var(--transition-theme);
  overflow-x: hidden;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 锚点平滑过渡及粘性顶部间距处理 */
[id] {
  scroll-margin-top: 86px;
}

main {
  flex: 1 0 auto;
}

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

img, svg {
  vertical-align: middle;
}

ul, ol {
  list-style: none;
}

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

/* --------------------------------------------------------------------------
   3. 布局与容器系统 (Airy Architectural Layout)
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 28px;
  padding-right: 28px;
}

.section {
  padding: 100px 0;
  position: relative;
}

.section-alt {
  background-color: var(--bg-surface-subtle);
  border-top: 1px solid var(--border-hairline);
  border-bottom: 1px solid var(--border-hairline);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 60px auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  color: var(--optical-blue);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 18px;
  box-shadow: var(--shadow-subtle);
}

.section-title {
  font-size: 2.45rem;
  font-weight: 800;
  line-height: 1.25;
  color: var(--text-charcoal);
  letter-spacing: -0.025em;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.75;
}

/* --------------------------------------------------------------------------
   4. 按钮系统 (Buttons & Interactive Triggers)
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 26px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-smooth);
  text-align: center;
  white-space: nowrap;
  user-select: none;
  min-height: 48px;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--text-charcoal);
  color: var(--bg-ceramic) !important;
  border: 1px solid transparent;
  box-shadow: 0 4px 14px rgba(18, 19, 22, 0.16);
}

[data-theme="dark"] .btn-primary {
  background: #ffffff;
  color: #0b0e14 !important;
  box-shadow: 0 4px 18px rgba(255, 255, 255, 0.2);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(18, 19, 22, 0.25);
  filter: brightness(1.08);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-charcoal);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-subtle);
  backdrop-filter: blur(10px);
}

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

.btn-lg {
  padding: 16px 36px;
  font-size: 1.05rem;
  min-height: 54px;
}

.btn-block {
  width: 100%;
}

/* --------------------------------------------------------------------------
   5. 页眉与光学微导航 (Header & Navigation Directory)
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-glass);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--border-hairline);
  transition: var(--transition-theme);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-charcoal);
  letter-spacing: -0.02em;
}

.logo-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--optical-blue) 0%, var(--optical-cyan) 100%);
  color: #ffffff;
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 12px rgba(9, 105, 218, 0.25);
  position: relative;
}

/* 导航链接目录 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color var(--transition-fast);
  padding: 8px 10px;
  border-radius: var(--radius-xs);
  position: relative;
}

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

.nav-link-badge {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--optical-blue);
  font-weight: 600;
}

.nav-link-badge .news-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #ef4444;
  box-shadow: 0 0 6px #ef4444;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* 精致半透明昼夜切换按钮 (无粗糙emoji，高质感SVG) */
.theme-toggle-btn {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  background: rgba(148, 163, 184, 0.1);
  border: 1px solid var(--border-hairline);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: var(--text-charcoal);
  transition: all var(--transition-smooth);
  cursor: pointer;
}

.theme-toggle-btn:hover {
  background: rgba(148, 163, 184, 0.2);
  border-color: var(--optical-blue);
  transform: rotate(15deg);
}

.theme-icon-sun, .theme-icon-moon {
  position: absolute;
  width: 19px;
  height: 19px;
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.4s ease;
}

.theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: #f59e0b;
}

.theme-icon-moon {
  opacity: 0;
  transform: rotate(90deg) scale(0.5);
  color: #38bdf8;
}

[data-theme="dark"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  color: var(--text-charcoal);
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
}

/* --------------------------------------------------------------------------
   6. 光学极简主视觉 (Hero Section & Bandwidth Wave Visualizer)
   -------------------------------------------------------------------------- */
.hero-section {
  padding: 110px 0 80px 0;
  position: relative;
  overflow: hidden;
  text-align: center;
}

/* 棱镜折射光晕背景 */
.hero-prism-refraction {
  position: absolute;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 460px;
  background: radial-gradient(ellipse at center, rgba(8, 145, 178, 0.12) 0%, rgba(9, 105, 218, 0.08) 35%, rgba(129, 140, 248, 0.04) 70%, transparent 80%);
  pointer-events: none;
  z-index: 0;
}

[data-theme="dark"] .hero-prism-refraction {
  background: radial-gradient(ellipse at center, rgba(34, 211, 238, 0.2) 0%, rgba(56, 189, 248, 0.14) 40%, transparent 75%);
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 900px;
  margin: 0 auto;
}

.hero-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 7px 18px;
  border-radius: var(--radius-full);
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  box-shadow: var(--shadow-subtle);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: 26px;
}

.hero-badge-pill .pulse-indicator {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #10b981;
  box-shadow: 0 0 10px #10b981;
}

/* 大标题包含当前品牌名 */
.hero-title {
  font-size: 3.6rem;
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -0.035em;
  color: var(--text-charcoal);
  margin-bottom: 24px;
}

.hero-title .brand-accent {
  background: linear-gradient(135deg, var(--optical-blue) 0%, var(--optical-cyan) 60%, var(--optical-indigo) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 780px;
  margin: 0 auto 36px auto;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 50px;
  flex-wrap: wrap;
}

/* 交互式无抖动协议切换器 (Protocol Switcher with Live Latency Metrics) */
.protocol-dashboard {
  background: var(--bg-glass-card);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 24px 28px;
  margin: 0 auto 40px auto;
  max-width: 820px;
  box-shadow: var(--shadow-card);
  transition: all var(--transition-smooth);
}

.protocol-dashboard:hover {
  border-color: var(--optical-blue);
  box-shadow: var(--shadow-floating);
}

.protocol-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
  flex-wrap: wrap;
  gap: 12px;
}

.protocol-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-charcoal);
  display: flex;
  align-items: center;
  gap: 8px;
}

.protocol-switcher {
  display: inline-flex;
  background: var(--bg-surface-subtle);
  padding: 4px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-hairline);
}

.protocol-btn {
  padding: 6px 14px;
  font-size: 0.8rem;
  font-weight: 600;
  border-radius: var(--radius-xs);
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

.protocol-btn.active {
  background: var(--bg-surface);
  color: var(--optical-blue);
  box-shadow: var(--shadow-subtle);
}

/* 实时专线延迟矩阵 (Precision Latency Metrics) */
.metrics-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.metric-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  text-align: left;
  transition: all var(--transition-fast);
}

.metric-card:hover {
  transform: translateY(-2px);
  border-color: var(--optical-blue);
}

.metric-city {
  font-size: 0.8rem;
  color: var(--text-subtle);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.metric-ping {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-charcoal);
  margin-top: 4px;
  display: flex;
  align-items: baseline;
  gap: 2px;
}

.metric-ping .unit {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-muted);
}

.status-dot-green {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #10b981;
}

/* 极简动态带宽波浪 (Live Bandwidth Wave Visualizer) */
.bandwidth-wave-wrap {
  width: 100%;
  height: 60px;
  overflow: hidden;
  position: relative;
  margin-top: 30px;
}

.bandwidth-wave-svg {
  width: 100%;
  height: 100%;
  opacity: 0.45;
}

[data-theme="dark"] .bandwidth-wave-svg {
  opacity: 0.65;
}

/* --------------------------------------------------------------------------
   7. 核心优势卡片 (Photonic Acrylic Server Cards - 3 Cards)
   -------------------------------------------------------------------------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-acrylic-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  position: relative;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-smooth);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}

/* 色散边缘交互 (Prismatic Rainbow Edge Glow) */
.feature-acrylic-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1.5px;
  background: var(--prism-border-active);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity var(--transition-smooth);
  pointer-events: none;
}

.feature-acrylic-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: transparent;
}

.feature-acrylic-card:hover::after {
  opacity: 1;
}

.feature-icon-wrapper {
  width: 54px;
  height: 54px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-hairline);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--optical-blue);
  margin-bottom: 24px;
  transition: transform var(--transition-smooth);
}

.feature-acrylic-card:hover .feature-icon-wrapper {
  transform: scale(1.08);
  border-color: var(--optical-blue);
}

.feature-card-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-charcoal);
  margin-bottom: 14px;
}

.feature-card-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 24px;
  flex-grow: 1;
}

.feature-stats-pill {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-hairline-subtle);
  font-size: 0.825rem;
  font-weight: 600;
  color: var(--text-muted);
}

.feature-stats-val {
  color: var(--optical-blue);
  font-weight: 700;
}

/* --------------------------------------------------------------------------
   8. 流媒体卡片 & AI 支持图卡 (Showcase Cards)
   -------------------------------------------------------------------------- */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.showcase-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 44px 36px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: all var(--transition-smooth);
}

.showcase-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  padding: 1.5px;
  background: var(--prism-border-active);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  opacity: 0;
  transition: opacity var(--transition-smooth);
  pointer-events: none;
}

.showcase-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: transparent;
}

.showcase-card:hover::after {
  opacity: 1;
}

.showcase-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}

.showcase-badge-icon {
  width: 50px;
  height: 50px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-hairline);
}

.showcase-media .showcase-badge-icon {
  background: rgba(239, 68, 68, 0.08);
  color: #ef4444;
}

.showcase-ai .showcase-badge-icon {
  background: rgba(16, 185, 129, 0.08);
  color: #10b981;
}

.showcase-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-charcoal);
}

.showcase-desc {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 26px;
}

.badge-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.service-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 7px 15px;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  background-color: var(--bg-surface-subtle);
  border: 1px solid var(--border-hairline);
  color: var(--text-charcoal);
  transition: all var(--transition-fast);
}

.service-pill:hover {
  border-color: var(--optical-blue);
  background-color: var(--bg-surface);
  transform: translateY(-2px);
}

.service-pill .pill-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
}

.showcase-stats-bar {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  padding-top: 24px;
  border-top: 1px solid var(--border-hairline);
  text-align: center;
}

.stat-num {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-charcoal);
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-subtle);
  margin-top: 2px;
}

/* --------------------------------------------------------------------------
   9. 网上真实套餐价格对比表 (Real-world Pricing Architecture)
   -------------------------------------------------------------------------- */
.pricing-cycle-toggle-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 48px;
}

.cycle-toggle-box {
  display: inline-flex;
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-full);
  padding: 4px;
}

.cycle-btn {
  padding: 8px 20px;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

.cycle-btn.active {
  background: var(--bg-surface);
  color: var(--text-charcoal);
  box-shadow: var(--shadow-subtle);
}

.discount-tag {
  background: rgba(239, 68, 68, 0.1);
  color: #ef4444;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: var(--radius-full);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-acrylic-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 36px 26px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-smooth);
  box-shadow: var(--shadow-card);
}

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

.pricing-acrylic-card.popular {
  border: 1.5px solid var(--optical-blue);
  box-shadow: var(--shadow-floating), 0 0 30px rgba(9, 105, 218, 0.15);
  transform: scale(1.02);
  z-index: 2;
}

.pricing-acrylic-card.popular:hover {
  transform: scale(1.02) translateY(-6px);
}

.plan-ribbon {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text-charcoal);
  color: var(--bg-ceramic);
  padding: 4px 16px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

[data-theme="dark"] .plan-ribbon {
  background: var(--optical-blue);
  color: #0b0e14;
}

.plan-tier-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-charcoal);
  margin-bottom: 8px;
}

.plan-target-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  min-height: 42px;
}

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

.price-currency {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-charcoal);
}

.price-val {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--text-charcoal);
  line-height: 1;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", sans-serif;
}

.price-period-label {
  font-size: 0.85rem;
  color: var(--text-subtle);
}

.plan-feature-checklist {
  display: flex;
  flex-direction: column;
  gap: 13px;
  margin-bottom: 32px;
  flex-grow: 1;
}

.feature-check-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 0.88rem;
  color: var(--text-main);
}

.feature-check-item svg {
  color: var(--optical-blue);
  width: 17px;
  height: 17px;
  flex-shrink: 0;
  margin-top: 3px;
}

/* --------------------------------------------------------------------------
   10. 用户评价 (Testimonials)
   -------------------------------------------------------------------------- */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.review-acrylic-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 34px 28px;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  transition: all var(--transition-smooth);
}

.review-acrylic-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-floating);
  border-color: var(--optical-blue);
}

.review-stars-row {
  display: flex;
  gap: 4px;
  color: #f59e0b;
  margin-bottom: 16px;
  font-size: 0.95rem;
}

.review-body-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 24px;
  flex-grow: 1;
}

.review-user-meta {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-monogram {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-subtle);
  border: 1px solid var(--border-hairline);
  color: var(--optical-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}

.user-full-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-charcoal);
}

.user-role-title {
  font-size: 0.8rem;
  color: var(--text-subtle);
}

/* --------------------------------------------------------------------------
   11. 常见问题 (FAQ Accordion)
   -------------------------------------------------------------------------- */
.faq-accordion-wrap {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item-box {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: all var(--transition-smooth);
}

.faq-item-box:hover {
  border-color: var(--optical-blue);
}

.faq-item-box.active {
  border-color: var(--optical-blue);
  box-shadow: var(--shadow-card);
}

.faq-trigger-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px 26px;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-charcoal);
  text-align: left;
  gap: 16px;
}

.faq-arrow-icon {
  width: 20px;
  height: 20px;
  transition: transform 0.35s ease;
  color: var(--text-muted);
  flex-shrink: 0;
}

.faq-item-box.active .faq-arrow-icon {
  transform: rotate(180deg);
  color: var(--optical-blue);
}

.faq-collapse-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 26px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.75;
}

.faq-item-box.active .faq-collapse-body {
  max-height: 380px;
  padding: 0 26px 24px 26px;
}

/* --------------------------------------------------------------------------
   12. 规范页脚 (Footer - 严格保留四个指定标题导航，在新页面打开)
   -------------------------------------------------------------------------- */
.site-footer {
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-hairline);
  padding: 50px 0 36px 0;
  transition: var(--transition-theme);
}

.footer-nav-list {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 36px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.footer-nav-link {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: color var(--transition-fast);
  padding: 6px 14px;
  border-radius: var(--radius-xs);
}

.footer-nav-link:hover {
  color: var(--optical-blue);
  background: var(--bg-surface-subtle);
}

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid var(--border-hairline);
  color: var(--text-subtle);
  font-size: 0.85rem;
}

.footer-brand-meta {
  margin-bottom: 8px;
  font-weight: 500;
  color: var(--text-muted);
}

/* --------------------------------------------------------------------------
   13. 独立页面与推荐资讯页样式 (Insights Hub & Subpages)
   -------------------------------------------------------------------------- */
.page-hero {
  padding: 70px 0 45px 0;
  background-color: var(--bg-surface-subtle);
  border-bottom: 1px solid var(--border-hairline);
}

.page-title {
  font-size: 2.35rem;
  font-weight: 800;
  color: var(--text-charcoal);
  margin-bottom: 12px;
}

.page-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
}

.prose {
  max-width: 860px;
  margin: 0 auto;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text-charcoal);
}

.prose h2 {
  font-size: 1.65rem;
  font-weight: 700;
  margin: 44px 0 16px 0;
  border-bottom: 1px solid var(--border-hairline);
  padding-bottom: 10px;
}

.prose h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 26px 0 12px 0;
}

.prose p {
  margin-bottom: 20px;
  color: var(--text-muted);
}

.prose ul, .prose ol {
  margin-bottom: 24px;
  padding-left: 24px;
  color: var(--text-muted);
}

.prose li {
  margin-bottom: 10px;
  list-style: disc;
}

.callout-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-left: 4px solid var(--optical-blue);
  border-radius: var(--radius-md);
  padding: 22px;
  margin: 28px 0;
}

.callout-box.alert-danger {
  border-left-color: #ef4444;
  background: rgba(239, 68, 68, 0.04);
}

.callout-box.alert-success {
  border-left-color: #10b981;
  background: rgba(16, 185, 129, 0.04);
}

/* 资讯列表网格 */
.insights-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 40px;
}

.insight-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-card);
  transition: all var(--transition-smooth);
  display: flex;
  flex-direction: column;
}

.insight-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-floating);
  border-color: var(--optical-blue);
}

.insight-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  background: var(--bg-surface-subtle);
  color: var(--optical-blue);
  margin-bottom: 16px;
  width: fit-content;
}

.insight-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-charcoal);
  margin-bottom: 12px;
  line-height: 1.4;
}

.insight-summary {
  font-size: 0.925rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 20px;
  flex-grow: 1;
}

.insight-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px solid var(--border-hairline);
  font-size: 0.8rem;
  color: var(--text-subtle);
}

/* --------------------------------------------------------------------------
   14. 移动端与平板响应式适配 (@media Queries)
   -------------------------------------------------------------------------- */
@media (max-width: 1080px) {
  .features-grid,
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .pricing-acrylic-card.popular {
    transform: none;
  }
  .pricing-acrylic-card.popular:hover {
    transform: translateY(-6px);
  }

  .metrics-row {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .section {
    padding: 60px 0;
  }

  .hero-section {
    padding: 70px 0 50px 0;
  }

  .hero-title {
    font-size: 2.35rem;
  }

  .hero-subtitle {
    font-size: 1.05rem;
  }

  .section-title {
    font-size: 1.85rem;
  }

  .hero-actions {
    flex-direction: column;
    width: 100%;
  }

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

  .features-grid,
  .showcase-grid,
  .pricing-grid,
  .reviews-grid,
  .insights-grid {
    grid-template-columns: 1fr;
  }

  .metrics-row {
    grid-template-columns: 1fr;
  }

  .menu-toggle {
    display: flex;
  }

  /* 移动端全宽折叠导航抽屉 */
  .nav-links {
    position: fixed;
    top: 76px;
    left: 0;
    right: 0;
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border-hairline);
    padding: 24px;
    flex-direction: column;
    gap: 12px;
    box-shadow: var(--shadow-floating);
    display: none;
    z-index: 999;
  }

  .nav-links.active {
    display: flex;
  }

  .nav-link {
    width: 100%;
    padding: 12px 14px;
    font-size: 1rem;
    border-radius: var(--radius-sm);
    background: var(--bg-surface-subtle);
  }

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

/* --------------------------------------------------------------------------
   15. SEO 深度长篇科普文章专属排版系统 (SEO Long-form Article Architecture)
   -------------------------------------------------------------------------- */
.article-wrap {
  padding: 50px 0 90px 0;
}

.article-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-subtle);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.article-breadcrumb a:hover {
  color: var(--optical-blue);
}

.article-header-box {
  margin-bottom: 40px;
  border-bottom: 1px solid var(--border-hairline);
  padding-bottom: 30px;
}

.article-badge-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: var(--radius-full);
  background: rgba(9, 105, 218, 0.08);
  color: var(--optical-blue);
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.article-main-title {
  font-size: 2.35rem;
  font-weight: 800;
  line-height: 1.3;
  color: var(--text-charcoal);
  margin-bottom: 18px;
  letter-spacing: -0.02em;
}

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

.article-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* 目录系统 (Table of Contents - TOC) */
.article-toc-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md);
  padding: 24px 28px;
  margin: 30px 0 40px 0;
  box-shadow: var(--shadow-subtle);
}

.article-toc-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-charcoal);
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-hairline-subtle);
}

.article-toc-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-left: 0 !important;
  list-style: none !important;
}

.article-toc-item {
  list-style: none !important;
  margin-bottom: 0 !important;
}

.article-toc-item a {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: all var(--transition-fast);
}

.article-toc-item a:hover {
  color: var(--optical-blue);
  transform: translateX(4px);
}

.article-toc-item.indent-h3 {
  padding-left: 20px;
  font-size: 0.9rem;
}

/* 文章表格与图表排版 */
.prose-table {
  width: 100%;
  border-collapse: collapse;
  margin: 28px 0;
  font-size: 0.925rem;
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.prose-table th,
.prose-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-hairline);
}

.prose-table th {
  background-color: var(--bg-surface-subtle);
  color: var(--text-charcoal);
  font-weight: 700;
}

.prose-table tr:hover td {
  background-color: rgba(9, 105, 218, 0.02);
}

/* 嵌入式 CTA 引导框 */
.article-cta-banner {
  background: linear-gradient(135deg, rgba(9, 105, 218, 0.05) 0%, rgba(6, 182, 212, 0.05) 100%);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin: 45px 0;
  text-align: center;
}

.article-cta-title {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text-charcoal);
  margin-bottom: 10px;
}

.article-cta-desc {
  font-size: 0.975rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  max-width: 650px;
  margin-left: auto;
  margin-right: auto;
}

/* 文章底部相关阅读推荐 (Related Articles Grid) */
.related-reads-section {
  margin-top: 60px;
  padding-top: 40px;
  border-top: 1px solid var(--border-hairline);
}

.related-reads-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-charcoal);
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.related-reads-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

@media (max-width: 900px) {
  .related-reads-grid {
    grid-template-columns: 1fr;
  }
  .article-main-title {
    font-size: 1.85rem;
  }
}

.related-read-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: all var(--transition-smooth);
  display: flex;
  flex-direction: column;
}

.related-read-card:hover {
  border-color: var(--optical-blue);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
}

.related-read-tag {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--optical-blue);
  margin-bottom: 8px;
}

.related-read-heading {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-charcoal);
  line-height: 1.4;
  margin-bottom: 10px;
  flex-grow: 1;
}

.related-read-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--optical-blue);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}