```css
/* ============================================
   红桃视频 - 完整样式表
   UI风格：深色渐变 + 毛玻璃 + 圆角卡片
   响应式：自适应PC/手机/平板
   暗色模式：支持系统偏好 + 手动切换
   动画：滚动显示、悬停微交互
   ============================================ */

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

/* ---------- 核心变量 ---------- */
:root {
  --bg-primary: #f8fafc;
  --bg-secondary: #eef2f7;
  --bg-card: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.65);
  --glass-border: rgba(255, 255, 255, 0.4);
  --text-primary: #1e293b;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-heading: #0f172a;
  --text-link: #2563eb;
  --text-white: #ffffff;
  --border-color: #cbd5e1;
  --nav-bg: rgba(15, 23, 42, 0.85);
  --nav-text: #f1f5f9;
  --btn-bg: #dc2626;
  --btn-hover: #b91c1c;
  --btn-text: #ffffff;
  --faq-bg: #f1f5f9;
  --footer-bg: #0f172a;
  --footer-text: #94a3b8;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
  --hero-grad-1: #0f172a;
  --hero-grad-2: #1e293b;
  --accent: #dc2626;
  --accent-soft: #f87171;
  --radius-sm: 12px;
  --radius-md: 18px;
  --radius-lg: 24px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --glass-blur: blur(14px);
}

/* 暗色模式 - 系统偏好 */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0b1120;
    --bg-secondary: #111827;
    --bg-card: #1e293b;
    --bg-glass: rgba(30, 41, 59, 0.6);
    --glass-border: rgba(148, 163, 184, 0.2);
    --text-primary: #e2e8f0;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --text-heading: #f8fafc;
    --text-link: #93c5fd;
    --border-color: #334155;
    --faq-bg: #1e293b;
    --footer-text: #94a3b8;
    --hero-grad-1: #0b1120;
    --hero-grad-2: #111827;
  }
}

/* 手动暗色模式类（JS切换） */
.dark-mode {
  --bg-primary: #0b1120;
  --bg-secondary: #111827;
  --bg-card: #1e293b;
  --bg-glass: rgba(30, 41, 59, 0.6);
  --glass-border: rgba(148, 163, 184, 0.2);
  --text-primary: #e2e8f0;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-heading: #f8fafc;
  --text-link: #93c5fd;
  --border-color: #334155;
  --faq-bg: #1e293b;
  --footer-text: #94a3b8;
}

/* ---------- 基础样式 ---------- */
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  font-size: 16px;
  transition: background-color 0.4s ease, color 0.3s ease;
  overflow-x: hidden;
}

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

a {
  color: var(--text-link);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent);
}

ul, ol {
  list-style: none;
}

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 滚动条美化 ---------- */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--accent);
  border-radius: 8px;
  border: 2px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--btn-hover);
}

/* ---------- 导航栏 ---------- */
.site-header {
  background: var(--nav-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  color: var(--nav-text);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.15);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  flex-wrap: wrap;
  gap: 12px;
}

.logo {
  font-size: 1.8rem;
  font-weight: 800;
  color: #ffffff;
  text-decoration: none;
  letter-spacing: -0.5px;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: opacity 0.2s;
}

.logo:hover {
  opacity: 0.85;
  color: #ffffff;
}

.logo span {
  color: var(--accent-soft);
}

.nav-links {
  display: flex;
  gap: 2.2rem;
  list-style: none;
  align-items: center;
}

.nav-links a {
  color: var(--nav-text);
  text-decoration: none;
  font-weight: 500;
  font-size: 1.02rem;
  padding: 6px 0;
  border-bottom: 2px solid transparent;
  transition: border-color 0.25s, color 0.2s;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-soft);
  transition: width 0.3s;
}

.nav-links a:hover {
  color: #ffffff;
}

.nav-links a:hover::after {
  width: 100%;
}

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

.search-box {
  display: flex;
  background: var(--bg-primary);
  border-radius: 50px;
  padding: 4px 16px 4px 6px;
  align-items: center;
  border: 1px solid var(--border-color);
  transition: box-shadow 0.3s, border-color 0.3s;
  backdrop-filter: var(--glass-blur);
}

.search-box:focus-within {
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.2);
  border-color: var(--accent);
}

.search-box input {
  border: none;
  background: transparent;
  padding: 8px 10px;
  width: 180px;
  color: var(--text-primary);
  outline: none;
  font-size: 0.95rem;
}

.search-box input::placeholder {
  color: var(--text-muted);
}

.icon-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--nav-text);
  font-size: 1.3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  border-radius: 50%;
  transition: background 0.2s, transform 0.2s;
  width: 40px;
  height: 40px;
}

.icon-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: scale(1.05);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 2rem;
  cursor: pointer;
  line-height: 1;
  padding: 4px;
}

/* 移动端导航抽屉 */
.mobile-nav {
  display: none;
  flex-direction: column;
  background: var(--nav-bg);
  backdrop-filter: var(--glass-blur);
  padding: 20px 24px;
  gap: 4px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
}

.mobile-nav.open {
  max-height: 500px;
  padding: 20px 24px;
}

.mobile-nav a {
  color: var(--nav-text);
  font-size: 1.1rem;
  text-decoration: none;
  padding: 12px 0;
  border-bottom: 1px solid rgba(148, 163, 184, 0.2);
  transition: padding-left 0.2s, color 0.2s;
}

.mobile-nav a:hover {
  padding-left: 12px;
  color: var(--accent-soft);
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  padding: 18px 0;
  color: var(--text-muted);
  font-size: 0.92rem;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--text-link);
  text-decoration: none;
  transition: color 0.2s;
}

.breadcrumb a:hover {
  color: var(--accent);
  text-decoration: underline;
}

/* ---------- Hero 区域 ---------- */
.hero-section {
  background: linear-gradient(135deg, var(--hero-grad-1) 0%, var(--hero-grad-2) 100%);
  color: white;
  padding: 70px 0 80px;
  position: relative;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(220, 38, 38, 0.15) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-section::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}

.hero-content {
  display: flex;
  align-items: center;
  gap: 50px;
  flex-wrap: wrap;
  position: relative;
  z-index: 2;
}

.hero-text {
  flex: 1 1 420px;
}

.hero-text h1 {
  font-size: 3.2rem;
  font-weight: 800;
  color: #ffffff;
  line-height: 1.15;
  margin-bottom: 24px;
  letter-spacing: -1px;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.hero-text p {
  font-size: 1.2rem;
  color: #cbd5e1;
  margin-bottom: 30px;
  max-width: 600px;
  line-height: 1.8;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--btn-bg);
  color: var(--btn-text);
  padding: 14px 36px;
  border-radius: 60px;
  font-weight: 700;
  text-decoration: none;
  font-size: 1.1rem;
  border: none;
  cursor: pointer;
  transition: all 0.3s;
  box-shadow: 0 4px 20px rgba(220, 38, 38, 0.35);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-primary:hover {
  background: var(--btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(220, 38, 38, 0.4);
}

.btn-secondary {
  background: transparent;
  color: white;
  padding: 14px 36px;
  border-radius: 60px;
  border: 2px solid var(--accent-soft);
  text-decoration: none;
  font-weight: 600;
  font-size: 1.1rem;
  transition: all 0.3s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-secondary:hover {
  background: rgba(248, 113, 113, 0.15);
  border-color: white;
  transform: translateY(-2px);
}

.hero-stats {
  display: flex;
  gap: 48px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--accent-soft);
  line-height: 1.2;
}

.stat-label {
  color: #94a3b8;
  font-size: 0.95rem;
  margin-top: 4px;
  letter-spacing: 0.5px;
}

.hero-image {
  flex: 1 1 320px;
  text-align: center;
  position: relative;
}

.hero-image svg {
  max-width: 100%;
  height: auto;
  border-radius: 24px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
  transition: transform 0.5s;
}

.hero-image svg:hover {
  transform: scale(1.02) rotate(1deg);
}

/* ---------- 通用区块 ---------- */
section {
  padding: 60px 0;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 20px;
  border-left: 6px solid var(--accent);
  padding-left: 18px;
  line-height: 1.3;
  letter-spacing: -0.5px;
}

.section-sub {
  color: var(--text-secondary);
  margin-bottom: 40px;
  font-size: 1.05rem;
}

/* ---------- 卡片系统 ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  background: var(--bg-glass);
  border: 1px solid var(--glass-border);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
  border-color: rgba(220, 38, 38, 0.3);
}

.card h3 {
  color: var(--text-heading);
  font-size: 1.4rem;
  margin-bottom: 12px;
  font-weight: 700;
}

.card h4 {
  color: var(--text-heading);
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.card p {
  color: var(--text-primary);
  margin-bottom: 8px;
}

/* 玻璃拟态专用 */
.glass-card {
  background: var(--bg-glass);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 28px;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
}

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

/* ---------- 网格布局 ---------- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 24px;
}

/* ---------- 文章卡片 ---------- */
.article-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 24px;
  border: 1px solid var(--border-color);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 10px;
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  background: var(--bg-glass);
  border: 1px solid var(--glass-border);
}

.article-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: rgba(220, 38, 38, 0.4);
}

.article-card h3 {
  color: var(--text-heading);
  font-size: 1.35rem;
  margin-bottom: 6px;
  line-height: 1.4;
  font-weight: 700;
}

.article-card p {
  color: var(--text-primary);
  flex-grow: 1;
}

.article-meta {
  color: var(--text-muted);
  font-size: 0.88rem;
  letter-spacing: 0.3px;
}

.article-card .text-link {
  color: var(--text-link);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: gap 0.2s, color 0.2s;
}

.article-card .text-link:hover {
  gap: 8px;
  color: var(--accent);
}

/* ---------- FAQ ---------- */
.faq-item {
  background: var(--faq-bg);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
  margin-bottom: 16px;
  border-left: 4px solid var(--accent);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.faq-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}

.faq-question {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text-heading);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  gap: 16px;
  user-select: none;
}

.faq-question span {
  font-size: 1.6rem;
  color: var(--accent);
  transition: transform 0.3s;
  flex-shrink: 0;
  line-height: 1;
}

.faq-item.active .faq-question span {
  transform: rotate(45deg);
}

.faq-answer {
  margin-top: 14px;
  color: var(--text-primary);
  line-height: 1.8;
  display: none;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
}

.faq-item.active .faq-answer {
  display: block;
}

/* ---------- HowTo 步骤 ---------- */
.howto-steps {
  list-style: none;
  counter-reset: step;
  margin: 20px 0;
}

.howto-steps li {
  counter-increment: step;
  padding: 14px 0;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  gap: 16px;
  align-items: flex-start;
  transition: padding-left 0.3s;
}

.howto-steps li:hover {
  padding-left: 8px;
}

.howto-steps li::before {
  content: counter(step);
  background: var(--accent);
  color: white;
  font-weight: 800;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1rem;
  box-shadow: 0 2px 8px rgba(220, 38, 38, 0.3);
}

/* ---------- 表格 ---------- */
.info-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.info-table th {
  background: #1e293b;
  color: white;
  padding: 14px;
  text-align: left;
  font-weight: 600;
}

.info-table td {
  padding: 14px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-primary);
  background: var(--bg-card);
}

.info-table tr:hover td {
  background: var(--bg-secondary);
}

/* ---------- 用户评价 ---------- */
.testimonial-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 28px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  position: relative;
  transition: var(--transition);
}

.testimonial-card::before {
  content: '"';
  position: absolute;
  top: 10px;
  left: 20px;
  font-size: 4rem;
  color: var(--accent);
  opacity: 0.2;
  font-family: Georgia, serif;
  line-height: 1;
}

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

.testimonial-card p:first-child {
  font-style: italic;
  margin-bottom: 16px;
  position: relative;
  z-index: 1;
}

.testimonial-card p:last-child {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--footer-bg);
  color: var(--footer-text);
  padding: 60px 0 30px;
  margin-top: 60px;
  position: relative;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-soft), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-grid h4 {
  color: #f8fafc;
  margin-bottom: 20px;
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.footer-grid a {
  color: var(--footer-text);
  text-decoration: none;
  display: block;
  margin-bottom: 10px;
  transition: color 0.2s, padding-left 0.2s;
  font-size: 0.95rem;
}

.footer-grid a:hover {
  color: white;
  padding-left: 6px;
}

.footer-grid p {
  color: var(--footer-text);
  line-height: 1.8;
}

.copyright {
  border-top: 1px solid #1e293b;
  margin-top: 30px;
  padding-top: 24px;
  text-align: center;
  color: #64748b;
  font-size: 0.9rem;
  line-height: 1.8;
}

/* ---------- 返回顶部按钮 ---------- */
#backTop {
  position: fixed;
  bottom: 40px;
  right: 30px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 50%;
  width: 52px;
  height: 52px;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(220, 38, 38, 0.4);
  z-index: 999;
  display: none;
  transition: all 0.3s;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

#backTop:hover {
  background: var(--btn-hover);
  transform: translateY(-4px);
  box-shadow: 0 10px 30px rgba(220, 38, 38, 0.5);
}

/* ---------- 交互状态 ---------- */
a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--accent-soft);
  outline-offset: 2px;
}

::selection {
  background: rgba(220, 38, 38, 0.3);
  color: var(--text-heading);
}

/* ---------- 友情链接区域 ---------- */
.friend-links {
  padding: 30px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid var(--border-color);
  margin-top: 20px;
}

.friend-links strong {
  color: var(--text-heading);
  margin-right: 8px;
}

.friend-links a {
  color: var(--text-link);
  transition: color 0.2s;
  margin: 0 4px;
}

.friend-links a:hover {
  color: var(--accent);
  text-decoration: underline;
}

/* ---------- 滚动动画（视口进入） ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* 交错延迟 */
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* ---------- 响应式设计 ---------- */
@media (max-width: 1024px) {
  .hero-text h1 {
    font-size: 2.6rem;
  }
  
  .hero-stats {
    gap: 30px;
  }
  
  .stat-number {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }

  .nav-links,
  .nav-actions .search-box {
    display: none;
  }

  .mobile-menu-btn {
    display: block;
  }

  .nav-wrap {
    padding: 12px 0;
  }

  .logo {
    font-size: 1.5rem;
  }

  .hero-section {
    padding: 50px 0 60px;
  }

  .hero-text h1 {
    font-size: 2.2rem;
  }

  .hero-text p {
    font-size: 1.05rem;
  }

  .hero-content {
    gap: 30px;
  }

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

  .btn-primary,
  .btn-secondary {
    width: 100%;
    text-align: center;
  }

  .hero-stats {
    gap: 24px;
    justify-content: center;
    width: 100%;
  }

  .stat-item {
    flex: 1;
    min-width: 80px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .section-title {
    font-size: 1.8rem;
  }

  .card,
  .article-card,
  .glass-card {
    padding: 20px;
  }

  .faq-item {
    padding: 16px 18px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 30px;
  }

  #backTop {
    bottom: 20px;
    right: 20px;
    width: 46px;
    height: 46px;
    font-size: 1.2rem;
  }

  .breadcrumb {
    font-size: 0.85rem;
    padding: 14px 0;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero-text h1 {
    font-size: 1.9rem;
  }

  .hero-stats {
    gap: 16px;
  }

  .stat-number {
    font-size: 1.7rem;
  }

  .stat-label {
    font-size: 0.85rem;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .friend-links {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .section-title {
    font-size: 1.6rem;
  }
}

/* ---------- 无障碍辅助 ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* ---------- 打印优化 ---------- */
@media print {
  .site-header,
  .hero-section,
  .site-footer,
  #backTop,
  .breadcrumb,
  .mobile-nav {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .card,
  .article-card,
  .faq-item {
    break-inside: avoid;
    box-shadow: none;
  }
}

/* ---------- 减少动效偏好 ---------- */
@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;
  }
}
```