/* ==========================================================================
   耶耶云 (YeyeCloud) - 全球高速专线网络加速服务
   原生极简纯 CSS 样式表 | 现代高品质浅色主题 (Light Mode)
   零外部依赖 | 极致秒开与全终端自适应
   ========================================================================== */

:root {
  /* 基础主色调体系 - 极简清爽明亮科技风 */
  --bg-primary: #f8fafc;        /* 整体背景底色 (Slate-50) */
  --bg-secondary: #ffffff;      /* 二级容器与卡片底色 */
  --bg-subtle: #f1f5f9;         /* 浅灰装饰块底色 (Slate-100) */
  --bg-card: #ffffff;           /* 卡片纯白背景 */
  --bg-card-hover: #ffffff;     /* 卡片悬浮状态 */
  
  --border-color: #e2e8f0;      /* 柔和浅灰边框 (Slate-200) */
  --border-hover: #cbd5e1;      /* 悬浮聚焦边框 (Slate-300) */
  --border-focus: #0284c7;      /* 重点强调边框 (Sky-600) */
  
  --text-main: #0f172a;         /* 主标题与正文强调色 (Slate-900) */
  --text-muted: #475569;        /* 描述文字与次要内容 (Slate-600) */
  --text-dim: #94a3b8;          /* 辅助文字与页脚次要 (Slate-400) */
  
  /* 科技品牌蓝与主渐变色 (针对浅色背景强化对比度与穿透力) */
  --primary: #0284c7;           /* 高对比度天空蓝 */
  --primary-hover: #0369a1;     /* 悬浮深蓝 */
  --primary-gradient: linear-gradient(135deg, #0284c7 0%, #4f46e5 100%);
  --accent-glow: rgba(2, 132, 199, 0.22);
  --accent-green: #059669;      /* 状态绿 */
  --accent-purple: #6366f1;     /* 装饰紫 */
  --accent-gold: #d97706;       /* 评级金黄 */
  
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 18px -2px rgba(15, 23, 42, 0.06), 0 2px 6px -1px rgba(15, 23, 42, 0.04);
  --shadow-lg: 0 12px 32px -4px rgba(15, 23, 42, 0.08), 0 4px 12px -2px rgba(15, 23, 42, 0.04);
  --shadow-featured: 0 16px 38px -6px rgba(2, 132, 199, 0.18), 0 6px 16px -2px rgba(2, 132, 199, 0.08);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --container-max: 1200px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  min-height: 100vh;
  line-height: 1.6;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(2, 132, 199, 0.08) 0%, transparent 45%),
    radial-gradient(circle at 90% 25%, rgba(99, 102, 241, 0.05) 0%, transparent 35%);
  background-attachment: fixed;
  overflow-x: hidden;
}

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

ul, ol {
  list-style: none;
}

img, svg {
  vertical-align: middle;
}

/* 容器布局 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 24px;
}

/* 顶部导航栏 (清爽半透明磨砂) */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
  box-shadow: 0 1px 6px rgba(0, 0, 0, 0.03);
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--text-main);
}

.brand-logo-icon {
  width: 34px;
  height: 34px;
  background: var(--primary-gradient);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px var(--accent-glow);
  font-size: 1.1rem;
  color: #fff;
}

.brand-logo-img {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  box-shadow: 0 3px 10px var(--accent-glow);
  display: block;
  transition: var(--transition);
}

.brand-logo:hover .brand-logo-img {
  transform: scale(1.08) rotate(-4deg);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 600;
}

.nav-links a:hover {
  color: var(--primary);
}

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

/* 通用按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #fff !important;
  box-shadow: 0 4px 16px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 22px rgba(2, 132, 199, 0.38);
}

.btn-secondary {
  background: #ffffff;
  color: var(--text-main);
  border-color: var(--border-color);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  background: var(--bg-subtle);
  border-color: var(--border-hover);
  color: var(--primary);
}

.btn-lg {
  padding: 14px 34px;
  font-size: 1.05rem;
  font-weight: 700;
}

/* 主视觉区 Hero */
.hero {
  padding: 85px 0 60px;
  text-align: center;
  position: relative;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 18px;
  border-radius: var(--radius-full);
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.22);
  color: var(--primary);
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero-badge .pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 8px var(--primary);
}

.hero-title {
  font-size: clamp(2.3rem, 5vw, 3.8rem);
  font-weight: 900;
  line-height: 1.22;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  color: var(--text-main);
}

.hero-title .gradient-text {
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 760px;
  margin: 0 auto 36px;
  line-height: 1.75;
}

.hero-cta-group {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

/* 首页主视觉美图插画展示 */
.hero-image-container {
  max-width: 960px;
  margin: 0 auto 36px;
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg), 0 0 30px rgba(2, 132, 199, 0.12);
  border: 1px solid var(--border-color);
  background: #ffffff;
  transition: var(--transition);
}

.hero-image-container:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-featured), 0 0 40px rgba(2, 132, 199, 0.2);
}

.hero-banner-image {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  display: block;
}

.hero-image-caption {
  padding: 12px 20px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-top: 1px solid var(--border-color);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  text-align: center;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 960px;
  margin: 40px auto 0;
  padding: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.stat-item h3,
.stat-item .stat-number {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
  display: block;
}

.stat-item p {
  color: var(--text-muted);
  font-size: 0.88rem;
  font-weight: 500;
}

/* 统一小节标题 */
.section {
  padding: 90px 0;
  position: relative;
}

.section-alt {
  background: #f1f5f9;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 54px;
}

.section-tag {
  display: inline-block;
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 800;
  line-height: 1.28;
  color: var(--text-main);
  margin-bottom: 14px;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.02rem;
  line-height: 1.68;
}

/* 核心优势网格 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  transition: var(--transition);
  position: relative;
  box-shadow: var(--shadow-sm);
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(2, 132, 199, 0.4);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.feature-icon-wrapper {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
  color: var(--primary);
}

.feature-card h3 {
  font-size: 1.22rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.94rem;
  line-height: 1.65;
}

/* 流媒体与 AI 支持专区 */
.services-showcase {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.showcase-block {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 32px;
  box-shadow: var(--shadow-md);
  position: relative;
}

.showcase-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
}

.showcase-header-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  background: rgba(99, 102, 241, 0.1);
  border: 1px solid rgba(99, 102, 241, 0.25);
  color: var(--accent-purple);
}

.showcase-block:first-child .showcase-header-icon {
  background: rgba(2, 132, 199, 0.1);
  border-color: rgba(2, 132, 199, 0.25);
  color: var(--primary);
}

.showcase-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-main);
}

.showcase-text {
  color: var(--text-muted);
  font-size: 0.96rem;
  margin-bottom: 24px;
  line-height: 1.65;
}

.tags-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.app-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  background: #f8fafc;
  border: 1px solid var(--border-color);
  font-size: 0.88rem;
  font-weight: 600;
  color: #334155;
  transition: var(--transition);
}

.app-tag:hover {
  background: rgba(2, 132, 199, 0.08);
  border-color: var(--primary);
  color: var(--primary);
}

.app-tag .tag-status {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-green);
  box-shadow: 0 0 6px rgba(5, 150, 105, 0.4);
}

/* 价格对比表 */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 38px 30px;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  position: relative;
  box-shadow: var(--shadow-sm);
}

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

.pricing-card.featured {
  background: linear-gradient(180deg, #ffffff 0%, #f0f7ff 100%);
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-featured);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-gradient);
  color: #fff;
  padding: 5px 18px;
  border-radius: var(--radius-full);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 12px var(--accent-glow);
}

.pricing-header {
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 24px;
  margin-bottom: 24px;
  text-align: center;
}

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

.plan-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 18px;
}

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

.currency {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--primary);
}

.amount {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1;
}

.period {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

.pricing-features {
  flex-grow: 1;
  margin-bottom: 30px;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.92rem;
  color: #334155;
  margin-bottom: 14px;
}

.pricing-features li .check-icon {
  color: var(--accent-green);
  font-weight: 800;
  font-size: 1.1rem;
}

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

/* 用户评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
}

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

.review-stars {
  color: var(--accent-gold);
  font-size: 1rem;
  margin-bottom: 14px;
  letter-spacing: 2px;
}

.review-text {
  font-size: 0.95rem;
  color: #334155;
  line-height: 1.68;
  margin-bottom: 22px;
  font-style: italic;
}

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

.reviewer-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
  border: 1px solid #bae6fd;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
}

.reviewer-info h4 {
  font-size: 0.94rem;
  font-weight: 700;
  color: var(--text-main);
}

.reviewer-info p {
  font-size: 0.82rem;
  color: var(--text-dim);
}

/* 常见问题 FAQ (纯 HTML details/summary 实现) */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

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

.faq-question {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  list-style: none; /* 去除原生三角符号 */
}

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

.faq-question::after {
  content: "+";
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--primary);
  transition: transform 0.25s ease;
}

.faq-item[open] .faq-question::after {
  content: "−";
  transform: rotate(0deg);
}

.faq-answer {
  padding: 0 24px 22px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid var(--border-color);
  padding-top: 14px;
}

/* 底部 CTA 激励横幅 */
.cta-banner {
  margin: 40px auto 0;
  max-width: var(--container-max);
  padding: 60px 40px;
  background: linear-gradient(135deg, #f0f9ff 0%, #e0e7ff 100%);
  border: 1px solid #bae6fd;
  border-radius: var(--radius-lg);
  text-align: center;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.cta-banner::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--primary-gradient);
}

.cta-banner h2 {
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 14px;
}

.cta-banner p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 620px;
  margin: 0 auto 30px;
}

/* 页脚 Footer - 严格保留四个标题 */
.footer {
  border-top: 1px solid var(--border-color);
  background: #ffffff;
  padding: 48px 0 36px;
  margin-top: 60px;
}

.footer-nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 40px;
  margin-bottom: 28px;
  flex-wrap: wrap;
}

.footer-nav a {
  color: var(--text-muted);
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.footer-nav a:hover {
  color: var(--primary);
  background: rgba(2, 132, 199, 0.08);
}

.footer-bottom {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.86rem;
  border-top: 1px solid var(--border-color);
  padding-top: 24px;
}

/* 子页面独立排版 (关于我们, 服务条款, 隐私政策, 网站地图) */
.subpage-header {
  padding: 65px 0 38px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
  background: #ffffff;
}

.subpage-title {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
}

.subpage-meta {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.article-content {
  max-width: 860px;
  margin: 50px auto 80px;
  padding: 0 24px;
}

.article-section {
  margin-bottom: 44px;
}

.article-section h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 10px;
}

.article-section h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--primary);
  margin: 18px 0 8px;
}

.article-section p, .article-section li {
  color: #334155;
  font-size: 0.96rem;
  line-height: 1.8;
  margin-bottom: 12px;
}

.article-section ul {
  padding-left: 20px;
  list-style-type: disc;
  margin-bottom: 16px;
}

.highlight-box {
  background: rgba(2, 132, 199, 0.06);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 18px 22px;
  margin: 20px 0;
}

.highlight-box p {
  color: var(--text-main);
  margin-bottom: 0;
}

.highlight-box.warning {
  background: rgba(245, 158, 11, 0.08);
  border-left-color: var(--accent-gold);
}

.nodes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  margin: 20px 0;
}

.node-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  box-shadow: var(--shadow-sm);
}

.node-item strong {
  color: var(--text-main);
  display: block;
  margin-bottom: 6px;
}

/* 网站地图链接网格 */
.sitemap-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 30px;
}

.sitemap-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}

.sitemap-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 14px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

.sitemap-card ul li {
  margin-bottom: 10px;
}

.sitemap-card ul li a {
  color: #334155;
  font-size: 0.94rem;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.sitemap-card ul li a:hover {
  color: var(--primary);
  transform: translateX(4px);
}

/* ==========================================================================
   高科技网格卡片 (High-Tech Grid Cards) - 推荐咨询专栏与 SEO 文章列表
   ========================================================================== */
.tech-article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 26px;
  margin: 36px 0 60px;
}

.tech-article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.tech-article-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--primary-gradient);
  opacity: 0;
  transition: opacity 0.25s ease;
}

.tech-article-card:hover {
  transform: translateY(-5px);
  border-color: rgba(2, 132, 199, 0.4);
  box-shadow: var(--shadow-featured);
}

.tech-article-card:hover::before {
  opacity: 1;
}

.tech-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.tech-card-badge {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--primary);
  background: rgba(2, 132, 199, 0.08);
  border: 1px solid rgba(2, 132, 199, 0.2);
  padding: 3px 10px;
  border-radius: var(--radius-full);
}

.tech-card-date {
  font-size: 0.8rem;
  color: var(--text-dim);
}

.tech-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.45;
  margin-bottom: 12px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.tech-article-card:hover .tech-card-title {
  color: var(--primary);
}

.tech-card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.tech-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border-color);
  padding-top: 14px;
}

.tech-card-meta {
  font-size: 0.82rem;
  color: var(--text-dim);
}

.tech-card-link {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.tech-card-link:hover {
  transform: translateX(3px);
}

/* ==========================================================================
   响应式适配 (@media 媒体查询)
   确保在手机端完美单栏显示，按钮适合手指触碰
   ========================================================================== */

@media (max-width: 992px) {
  .features-grid,
  .pricing-grid,
  .reviews-grid,
  .tech-article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .navbar-container {
    padding: 0;
  }
  
  .nav-links {
    display: none; /* 移动端隐藏冗余文字链接，专注高转化 CTA */
  }
  
  .hero {
    padding: 50px 0 40px;
  }
  
  .hero-title {
    font-size: 2.1rem;
  }
  
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-cta-group .btn {
    width: 100%;
    min-height: 48px;
    font-size: 1.05rem;
  }
  
  .hero-stats {
    grid-template-columns: 1fr;
    gap: 16px;
    padding: 18px;
  }
  
  .features-grid,
  .services-showcase,
  .pricing-grid,
  .reviews-grid,
  .nodes-grid,
  .sitemap-grid,
  .tech-article-grid {
    grid-template-columns: 1fr; /* 完美单栏排版 */
  }
  
  .pricing-card.featured {
    order: -1; /* 移动端将最受欢迎套餐置顶突出 */
  }
  
  .pricing-card .btn {
    min-height: 48px;
  }
  
  .footer-nav {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }
  
  .footer-nav a {
    width: 100%;
    padding: 10px 0;
    font-size: 1.05rem;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .cta-banner {
    padding: 40px 20px;
  }
  
  .cta-banner .btn {
    width: 100%;
    min-height: 48px;
  }
}