/* 
  老头VPN laotouvpn - 极简主义设计系统
  配色：#FFFFFF 纯白底 | #1A1A1A 近黑 | #4A90E2 单一强调蓝 | #F5F5F5 浅灰
  特征：极度克制，大量留白（70%+），直角无圆角（border-radius: 0），无阴影
*/

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f5;
  --bg-card: #ffffff;
  --bg-card-hover: #fafafa;
  --border-color: #e5e5e5;
  --border-dark: #1a1a1a;
  --border-highlight: #4a90e2;
  --primary: #4a90e2;
  --primary-hover: #357abd;
  --text-main: #1a1a1a;
  --text-muted: #555555;
  --text-dim: #888888;
  --radius: 0px;
  --container-width: 1200px;
  --transition: all 0.2s ease-in-out;
}

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

/* 长文本与无障碍基础 */
p, h1, h2, h3, h4, h5, h6, li, td, th {
  overflow-wrap: break-word;
}

/* 无障碍：键盘快速跳转到主内容 */
.skip-link {
  position: absolute;
  top: -9999px;
  left: 1.5rem;
  z-index: 99999;
  padding: 0.75rem 1.5rem;
  background-color: #1a1a1a;
  color: #ffffff !important;
  font-weight: 600;
  border: 2px solid var(--primary);
  text-decoration: none;
}

.skip-link:focus, .skip-link:focus-visible {
  top: 1.5rem;
  outline: none;
}

/* 键盘焦点可见轮廓 */
a:focus-visible, button:focus-visible, summary:focus-visible, input:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-primary);
}

body {
  font-family: "Inter", "Helvetica Neue", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-weight: 400;
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
  -webkit-font-smoothing: antialiased;
}

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

ul {
  list-style: none;
}

img, svg {
  vertical-align: middle;
}

.container {
  width: 100%;
  max-width: var(--container-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 2rem;
  padding-right: 2rem;
  position: relative;
  z-index: 1;
}

/* ==========================================================================
   背景动效 (全屏纯白底 + 中央扩散涟漪 + 1px浅灰水平细线)
   ========================================================================== */
.bg-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
  background: #ffffff;
}

/* 中央浅灰圆形涟漪 (半径 200px, 慢扩散 scale 1 -> 3, opacity 0.3 -> 0, 每4秒生成一个) */
.ripple {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 400px;
  height: 400px;
  margin-top: -200px;
  margin-left: -200px;
  border-radius: 50%;
  border: 1px solid #e0e0e0;
  background-color: #f5f5f5;
  transform-origin: center center;
  animation: rippleSpread 8s cubic-bezier(0.2, 0.4, 0.4, 1) infinite;
}

.ripple-2 {
  animation-delay: 4s;
}

@keyframes rippleSpread {
  0% {
    transform: scale(1);
    opacity: 0.3;
  }
  100% {
    transform: scale(3);
    opacity: 0;
  }
}

/* 1px 浅灰水平细线从左到右缓慢移动（10 秒一周期） */
.scanline-track {
  position: absolute;
  top: 45%;
  left: 0;
  width: 100vw;
  height: 1px;
  overflow: hidden;
}

.scanline-bar {
  position: absolute;
  top: 0;
  left: -40%;
  width: 40%;
  height: 1px;
  background: linear-gradient(90deg, transparent, #e5e5e5, #cccccc, #e5e5e5, transparent);
  animation: scanlineMove 10s linear infinite;
}

@keyframes scanlineMove {
  0% {
    transform: translateX(0);
    left: -40%;
  }
  100% {
    transform: translateX(calc(100vw + 80%));
    left: -40%;
  }
}

/* ==========================================================================
   页眉与导航
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  padding: 1.25rem 0;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--text-main);
  letter-spacing: -0.03em;
}

.brand-logo svg {
  width: 28px;
  height: 28px;
}

.logo-badge {
  font-weight: 500;
  color: var(--text-dim);
  font-size: 0.9rem;
  margin-left: 0.2rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2.25rem;
}

.nav-link {
  color: var(--text-muted);
  font-weight: 400;
  font-size: 0.95rem;
  position: relative;
  padding: 0.25rem 0;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* ==========================================================================
   按钮规范 (黑色填充，白字，hover变蓝，圆角0，无阴影)
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 2rem;
  min-height: 44px;
  min-width: 44px;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 0 !important;
  box-shadow: none !important;
  cursor: pointer;
  border: 1px solid #1a1a1a;
  transition: var(--transition);
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background-color: #1a1a1a !important;
  color: #ffffff !important;
  border-color: #1a1a1a !important;
}

.btn-primary:hover {
  background-color: var(--primary) !important;
  border-color: var(--primary) !important;
  color: #ffffff !important;
}

.btn-secondary {
  background-color: #ffffff !important;
  color: #1a1a1a !important;
  border-color: #1a1a1a !important;
}

.btn-secondary:hover {
  background-color: #1a1a1a !important;
  color: #ffffff !important;
}

.btn-lg {
  padding: 1.1rem 2.75rem;
  font-size: 1.05rem;
  min-height: 52px;
}

.btn-sm {
  padding: 0.65rem 1.4rem;
  font-size: 0.875rem;
  min-height: 44px;
}

.btn-block {
  width: 100%;
}

/* ==========================================================================
   主视觉区 (Hero Section: 大标题超大字体 + 盾牌SVG绘制动画)
   ========================================================================== */
.hero-section {
  padding: 7rem 0 5rem;
  position: relative;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.35rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  font-size: 0.825rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
}

.pulse-dot {
  width: 6px;
  height: 6px;
  background-color: var(--primary);
  border-radius: 50%;
}

/* 大标题布局：左侧 H1 120px+，右侧 100px 极简线条盾牌 SVG */
.hero-headline-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 3rem;
}

.hero-headline-left {
  flex: 1;
}

.hero-title-main {
  font-family: "Inter", "Helvetica Neue", sans-serif;
  font-size: clamp(72px, 10vw, 132px);
  font-weight: 900;
  line-height: 0.92;
  letter-spacing: -0.05em;
  color: #1a1a1a;
  margin-bottom: 1rem;
}

.hero-brand-sub {
  font-size: 1.25rem;
  color: var(--text-dim);
  font-weight: 400;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* 右侧 100px 线条盾牌动画 */
.hero-shield-wrap {
  position: relative;
  width: 100px;
  height: 100px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.shield-svg {
  width: 100px;
  height: 100px;
  overflow: visible;
}

/* 路径从下到上绘制 2 秒，停留 1 秒，反向擦除 1 秒，循环 (周期 4s) */
.shield-path {
  stroke-dasharray: 100;
  stroke-dashoffset: 100;
  animation: drawShield 4s ease-in-out infinite;
}

@keyframes drawShield {
  0% {
    stroke-dashoffset: 100;
  }
  50% { /* 2秒绘制完毕 */
    stroke-dashoffset: 0;
  }
  75% { /* 停留1秒 (2s -> 3s) */
    stroke-dashoffset: 0;
  }
  100% { /* 1秒擦除完毕 (3s -> 4s) */
    stroke-dashoffset: 100;
  }
}

/* 盾牌中央 4px 强调色蓝点呼吸闪烁 */
.shield-dot {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 4px;
  height: 4px;
  margin-top: -2px;
  margin-left: -2px;
  background-color: var(--primary);
  border-radius: 50%;
  animation: dotBreath 2s ease-in-out infinite;
}

@keyframes dotBreath {
  0%, 100% {
    opacity: 0.25;
    transform: scale(0.8);
  }
  50% {
    opacity: 1;
    transform: scale(1.6);
  }
}

.hero-subtitle {
  font-size: 1.35rem;
  color: var(--text-muted);
  max-width: 820px;
  margin-bottom: 3rem;
  font-weight: 400;
  line-height: 1.8;
}

/* 主视觉区服务简介 (Hero Intro Box) - 纯白极简留白风格 */
.hero-intro-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 2.5rem 3rem;
  max-width: 900px;
  margin-bottom: 3.5rem;
  border-left: 3px solid #1a1a1a;
}

.hero-intro-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 1rem;
}

.hero-intro-text {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.9;
  margin-bottom: 1.5rem;
}

.hero-intro-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.hero-intro-pill-item {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.85rem;
  background: var(--bg-secondary);
  padding: 0.4rem 0.9rem;
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.hero-intro-pill-item svg {
  color: var(--primary);
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 3.5rem;
}

.hero-guarantee {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 2.5rem;
  color: var(--text-dim);
  font-size: 0.875rem;
  border-top: 1px solid var(--border-color);
  padding-top: 2rem;
}

.hero-guarantee-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.hero-guarantee-item svg {
  color: #1a1a1a;
}

/* ==========================================================================
   各内容版块通栏 (留白占比 70%+, 极简黑白线条)
   ========================================================================== */
.section {
  padding: 7rem 0;
  border-top: 1px solid var(--border-color);
}

.section-title-wrap {
  margin-bottom: 4.5rem;
}

.section-tag {
  color: var(--primary);
  text-transform: uppercase;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  margin-bottom: 0.75rem;
  display: block;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 900;
  letter-spacing: -0.03em;
  color: #1a1a1a;
  margin-bottom: 1rem;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 650px;
}

/* 核心优势 3 张卡片 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.5rem;
}

.feature-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 3rem 2.25rem;
  transition: var(--transition);
  position: relative;
}

.feature-card:hover {
  border-color: #1a1a1a;
}

.feature-icon-box {
  width: 52px;
  height: 52px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 2rem;
  color: #1a1a1a;
}

.feature-title {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: #1a1a1a;
  letter-spacing: -0.02em;
}

.feature-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.8;
}

/* 流媒体与 AI 生态卡片 */
.eco-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
}

.eco-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 3rem 2.5rem;
}

.eco-card-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.eco-badge {
  padding: 0.25rem 0.65rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: #1a1a1a;
  font-size: 0.725rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.eco-card-title {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.eco-card-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 2.5rem;
  line-height: 1.7;
}

.eco-tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.eco-tag-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 0.65rem 1.1rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: #1a1a1a;
  transition: var(--transition);
}

.eco-tag-item:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.eco-tag-item svg {
  width: 18px;
  height: 18px;
}

/* ==========================================================================
   套餐价格对比表 (真实套餐价格 + 极简主义黑白线框)
   ========================================================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.5rem;
  align-items: stretch;
}

.pricing-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 3.5rem 2.5rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.pricing-card:hover {
  border-color: #1a1a1a;
}

.pricing-card.featured {
  border: 2px solid #1a1a1a;
}

.pricing-badge-popular {
  position: absolute;
  top: -14px;
  left: 2rem;
  background: #1a1a1a;
  color: #ffffff;
  font-size: 0.725rem;
  font-weight: 600;
  padding: 0.3rem 0.85rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.plan-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  min-height: 48px;
  margin-bottom: 1.75rem;
}

.plan-price-wrap {
  margin-bottom: 1.75rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--border-color);
}

.plan-price-row {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 0.35rem;
}

.plan-currency {
  font-size: 1.4rem;
  font-weight: 700;
  color: #1a1a1a;
  white-space: nowrap;
}

.plan-price {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.03em;
  color: #1a1a1a;
  white-space: nowrap !important;
  word-break: keep-all !important;
}

.plan-period {
  color: var(--text-dim);
  font-size: 0.875rem;
  white-space: nowrap;
}

.plan-price-sub {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.825rem;
}

.plan-original {
  text-decoration: line-through;
  color: var(--text-dim);
}

.plan-tag-save {
  background: var(--bg-secondary);
  color: var(--primary);
  border: 1px solid var(--border-color);
  padding: 0.15rem 0.5rem;
  font-weight: 600;
}

.plan-speed-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  background: var(--bg-secondary);
  padding: 0.4rem 0.75rem;
  border: 1px solid var(--border-color);
  margin-bottom: 1.75rem;
}

.plan-features {
  flex-grow: 1;
  margin-bottom: 2.5rem;
}

.plan-feature-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.925rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.plan-feature-item svg {
  color: var(--primary);
  flex-shrink: 0;
  width: 16px;
  height: 16px;
}

.plan-feature-item.highlight {
  color: #1a1a1a;
  font-weight: 500;
}

/* ==========================================================================
   用户评价 (留白 + 极简纯净卡片)
   ========================================================================== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2.5rem;
}

.review-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 2.75rem 2.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
}

.review-card:hover {
  border-color: #1a1a1a;
}

.review-stars {
  color: var(--primary);
  margin-bottom: 1.25rem;
  letter-spacing: 0.15em;
  font-size: 0.95rem;
}

.review-quote {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 2rem;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.25rem;
}

.review-avatar {
  width: 40px;
  height: 40px;
  background: #1a1a1a;
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.9rem;
}

.review-name {
  font-weight: 600;
  font-size: 0.925rem;
  color: #1a1a1a;
}

.review-role {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* ==========================================================================
   常见问题解答 (FAQ)
   ========================================================================== */
.faq-wrap {
  max-width: 900px;
}

.faq-item {
  background: #ffffff;
  border: 1px solid var(--border-color);
  margin-bottom: 1.25rem;
  transition: var(--transition);
}

.faq-item[open] {
  border-color: #1a1a1a;
}

.faq-question {
  padding: 1.5rem 2rem;
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  list-style: none;
  color: #1a1a1a;
}

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

.faq-arrow {
  width: 18px;
  height: 18px;
  transition: transform 0.2s ease;
  color: var(--text-dim);
  flex-shrink: 0;
}

.faq-item[open] .faq-arrow {
  transform: rotate(180deg);
  color: #1a1a1a;
}

.faq-answer {
  padding: 0 2rem 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.9;
  border-top: 1px solid var(--border-color);
  padding-top: 1.25rem;
}

/* ==========================================================================
   底部行动转化区 (CTA Banner)
   ========================================================================== */
.cta-banner {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 5rem 3rem;
  text-align: center;
  margin: 5rem 0 2rem;
}

.cta-banner h2 {
  font-size: 2.5rem;
  font-weight: 900;
  letter-spacing: -0.03em;
  color: #1a1a1a;
  margin-bottom: 1rem;
}

.cta-banner p {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 620px;
  margin: 0 auto 2.5rem;
}

/* ==========================================================================
   页脚 (严格只保留这4个标题，内容打开新页面)
   ========================================================================== */
.site-footer {
  border-top: 1px solid var(--border-color);
  background: #ffffff;
  padding: 4rem 0 3rem;
  margin-top: 6rem;
  position: relative;
  z-index: 1;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 3rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.footer-link {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 0.4rem 0;
}

.footer-link:hover {
  color: var(--primary);
}

.footer-bottom {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--border-color);
}

/* ==========================================================================
   独立子页面样式 (关于我们、服务条款、隐私政策、知识科普、网站地图)
   ========================================================================== */
.page-header {
  padding: 5rem 0 3rem;
  border-bottom: 1px solid var(--border-color);
  background: #ffffff;
  position: relative;
  z-index: 1;
}

.page-title {
  font-size: 2.75rem;
  font-weight: 900;
  letter-spacing: -0.03em;
  color: #1a1a1a;
  margin-bottom: 0.75rem;
}

.page-subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 700px;
}

.page-content {
  padding: 4rem 0 6rem;
  max-width: 860px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.content-block {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 3rem;
  margin-bottom: 2.5rem;
}

.content-block h2 {
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
  color: #1a1a1a;
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.content-block p {
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 1.25rem;
}

.content-block ul {
  list-style: disc;
  margin-left: 1.5rem;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 1.25rem;
}

.content-block li {
  margin-bottom: 0.6rem;
}

.badge-green {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--primary);
  padding: 0.25rem 0.6rem;
  font-size: 0.85rem;
  font-weight: 600;
}

/* ==========================================================================
   知识科普 SEO 深度文章与目录系统
   ========================================================================== */
.seo-toc-container {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 2.5rem;
  margin-bottom: 3.5rem;
}

.seo-toc-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: #1a1a1a;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.seo-toc-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 1.75rem;
}

.seo-toc-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.seo-toc-item {
  border: 1px solid var(--border-color);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  background: #ffffff;
}

.seo-toc-item:hover {
  border-color: #1a1a1a;
  transform: translateY(-2px);
}

.seo-toc-number {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}

.seo-toc-item-title {
  font-size: 0.925rem;
  font-weight: 700;
  color: #1a1a1a;
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

.seo-toc-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-dim);
  border-top: 1px solid var(--border-color);
  padding-top: 0.6rem;
}

/* 单篇文章排版卡片 */
.seo-article-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 3.5rem 3rem;
  margin-bottom: 3.5rem;
  scroll-margin-top: 100px;
}

.seo-article-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 1.75rem;
  margin-bottom: 2rem;
}

.seo-meta-info {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-bottom: 1rem;
}

.seo-tag-pill {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: #1a1a1a;
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
}

.seo-word-count {
  background: rgba(74, 144, 226, 0.1);
  border: 1px solid rgba(74, 144, 226, 0.3);
  color: var(--primary);
  padding: 0.2rem 0.6rem;
  font-size: 0.75rem;
  font-weight: 600;
}

.seo-article-title {
  font-size: 1.85rem;
  font-weight: 900;
  line-height: 1.4;
  letter-spacing: -0.03em;
  color: #1a1a1a;
}

.seo-body h3 {
  font-size: 1.25rem;
  font-weight: 800;
  color: #1a1a1a;
  margin: 1.75rem 0 0.85rem;
  letter-spacing: -0.02em;
}

.seo-body p {
  color: #444444;
  font-size: 1rem;
  line-height: 1.95;
  margin-bottom: 1.25rem;
}

.seo-body ul {
  list-style: disc;
  margin-left: 1.5rem;
  color: #444444;
  line-height: 1.9;
  margin-bottom: 1.5rem;
}

.seo-body li {
  margin-bottom: 0.5rem;
}

.seo-highlight-box {
  background: var(--bg-secondary);
  border-left: 3px solid var(--primary);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  color: #333333;
  line-height: 1.8;
}

.seo-internal-link {
  color: var(--primary);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: var(--transition);
}

.seo-internal-link:hover {
  color: #1a1a1a;
}

.seo-card-cta-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 1.25rem 1.75rem;
  margin-top: 2rem;
}

.seo-card-cta-bar span {
  font-size: 0.95rem;
  font-weight: 600;
  color: #1a1a1a;
}

/* 9 篇文章内专属 FAQ 样式 */
.seo-faq-section {
  margin-top: 2.25rem;
  padding-top: 2rem;
  border-top: 1px dashed var(--border-color);
}

.seo-faq-section-title {
  font-size: 1.15rem;
  font-weight: 800;
  color: #1a1a1a;
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.seo-article-faq-item {
  background: #ffffff;
  border: 1px solid var(--border-color);
  margin-bottom: 0.85rem;
  transition: var(--transition);
}

.seo-article-faq-item[open] {
  border-color: #1a1a1a;
  background: #fafafa;
}

.seo-article-faq-q {
  padding: 1.1rem 1.35rem;
  font-size: 0.95rem;
  font-weight: 700;
  color: #1a1a1a;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

.seo-article-faq-q::-webkit-details-marker {
  display: none;
}

.seo-article-faq-icon {
  font-size: 0.8rem;
  color: var(--primary);
  transition: transform 0.2s ease;
}

.seo-article-faq-item[open] .seo-article-faq-icon {
  transform: rotate(180deg);
  color: #1a1a1a;
}

.seo-article-faq-a {
  padding: 0 1.35rem 1.15rem;
  font-size: 0.925rem;
  color: #555555;
  line-height: 1.85;
  border-top: 1px solid var(--border-color);
  padding-top: 0.85rem;
}

/* 文章关联推荐内链列表 */
.seo-cross-links-box {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 1.25rem 1.5rem;
  margin-top: 1.75rem;
  font-size: 0.9rem;
}

.seo-cross-links-title {
  font-weight: 700;
  color: #1a1a1a;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.seo-cross-links-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1.5rem;
}



/* ==========================================================================
   响应式媒体查询 (@media)
   ========================================================================== */
@media (max-width: 1024px) {
  .hero-title-main {
    font-size: 84px;
  }
  .features-grid, .pricing-grid, .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.75rem;
  }
}

@media (max-width: 768px) {
  .site-header {
    padding: 1rem 0;
  }

  .nav-links {
    display: none;
  }

  .hero-section {
    padding: 3.5rem 0 2.5rem;
  }

  .hero-headline-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.5rem;
    padding-bottom: 2rem;
  }

  .hero-title-main {
    font-size: 64px;
    line-height: 1;
  }

  .hero-shield-wrap {
    width: 80px;
    height: 80px;
  }

  .shield-svg {
    width: 80px;
    height: 80px;
  }

  .hero-subtitle {
    font-size: 1.05rem;
    margin-bottom: 2rem;
  }

  .hero-intro-box {
    padding: 1.75rem 1.5rem;
  }

  .hero-cta-group {
    flex-direction: column;
    width: 100%;
    gap: 1rem;
  }

  .hero-cta-group .btn {
    width: 100%;
    min-height: 52px;
  }

  .features-grid, .pricing-grid, .reviews-grid, .eco-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .feature-card, .eco-card, .pricing-card, .review-card {
    padding: 2.25rem 1.75rem;
  }

  .section {
    padding: 4.5rem 0;
  }

  .section-title {
    font-size: 2rem;
  }

  .footer-nav {
    flex-direction: column;
    gap: 1.25rem;
  }

  .footer-link {
    font-size: 1rem;
    display: block;
    width: 100%;
    text-align: center;
  }

  .cta-banner {
    padding: 3rem 1.5rem;
    margin: 3rem 0 1rem;
  }

  .cta-banner h2 {
    font-size: 1.85rem;
  }

  .page-title {
    font-size: 2rem;
  }

  .content-block {
    padding: 2rem 1.5rem;
  }
}

/* ==========================================================================
   套餐对比语义表格 (Accessible Pricing Table)
   ========================================================================== */
.pricing-table-container {
  width: 100%;
  overflow-x: auto;
  margin-top: 3.5rem;
  border: 1px solid var(--border-color);
  background: #ffffff;
  -webkit-overflow-scrolling: touch;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
  min-width: 640px;
}

.pricing-table caption {
  padding: 1.25rem 1.5rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  text-align: left;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-secondary);
}

.pricing-table th, .pricing-table td {
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
  vertical-align: middle;
}

.pricing-table th:last-child, .pricing-table td:last-child {
  border-right: none;
}

.pricing-table thead th {
  background: #fafafa;
  font-weight: 700;
  color: var(--text-main);
}

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

.pricing-table tbody tr:hover td {
  background-color: #fafafa;
}

/* ==========================================================================
   用户评价综合评分徽章 (与 Schema 互证)
   ========================================================================== */
.reviews-summary-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 1.25rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  margin-bottom: 2.5rem;
  font-size: 0.95rem;
}

.reviews-summary-badge .stars {
  color: #ff9800;
  font-size: 1.15rem;
  letter-spacing: 2px;
}

.reviews-summary-badge .score strong {
  font-weight: 700;
  color: var(--text-main);
}

.reviews-summary-badge .count {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ==========================================================================
   独立文章页排版规范 (Single Article View)
   ========================================================================== */
.article-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 4rem 2rem 6rem;
}

.article-header {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
}

.article-breadcrumbs {
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

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

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

.article-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-top: 1rem;
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.85;
  color: #222222;
}

.article-content h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.article-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-main);
  margin: 2rem 0 0.75rem;
}

.article-content p {
  margin-bottom: 1.25rem;
}

.article-content ul, .article-content ol {
  margin: 1rem 0 1.5rem 1.5rem;
}

.article-content li {
  margin-bottom: 0.5rem;
  list-style: disc;
}

.article-content blockquote {
  border-left: 3px solid var(--primary);
  padding: 0.75rem 1.25rem;
  margin: 1.5rem 0;
  background-color: var(--bg-secondary);
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ==========================================================================
   无障碍：减弱动态模式 (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;
  }
  .ripple, .scanline-bar, .shield-svg-path {
    animation: none !important;
  }
}