```css
/* ============================================
   51视频 - 完整样式系统
   风格：渐变霓虹 + 毛玻璃 + 微交互
   支持：暗色模式 / 响应式 / 滚动动画
   ============================================ */

/* ---------- 主题变量 ---------- */
:root {
  --bg: #f4f6fb;
  --bg-gradient: radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
                 radial-gradient(circle at 80% 0%, rgba(168, 85, 247, 0.06) 0%, transparent 40%),
                 linear-gradient(180deg, #f4f6fb 0%, #eef1f8 100%);
  --card-bg: rgba(255, 255, 255, 0.7);
  --card-border: rgba(255, 255, 255, 0.6);
  --text: #1e2433;
  --muted: #6b7280;
  --primary: #4f46e5;
  --primary-light: #818cf8;
  --primary-dark: #3730a3;
  --accent: #a855f7;
  --accent-light: #c084fc;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --border: rgba(30, 36, 51, 0.08);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.08);
  --shadow-primary: 0 8px 30px rgba(79, 70, 229, 0.2);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --blur: blur(16px);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --max-width: 1280px;
}

[data-theme="dark"] {
  --bg: #0b1020;
  --bg-gradient: radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
                 radial-gradient(circle at 80% 80%, rgba(168, 85, 247, 0.1) 0%, transparent 40%),
                 linear-gradient(180deg, #0b1020 0%, #0f172a 100%);
  --card-bg: rgba(30, 41, 59, 0.8);
  --card-border: rgba(148, 163, 184, 0.15);
  --text: #e2e8f0;
  --muted: #94a3b8;
  --border: rgba(148, 163, 184, 0.15);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.5);
  --shadow-primary: 0 8px 30px rgba(79, 70, 229, 0.3);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font);
  background: var(--bg);
  background-image: var(--bg-gradient);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  transition: background 0.4s ease, color 0.3s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

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

input {
  font-family: inherit;
  border: none;
  outline: none;
  background: transparent;
}

ul, ol {
  list-style: none;
}

::selection {
  background: var(--primary);
  color: #fff;
}

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

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  border-radius: 10px;
  border: 2px solid transparent;
  background-clip: padding-box;
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  background-clip: padding-box;
}

/* ---------- 通用容器 ---------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   导航栏 - 毛玻璃吸顶
   ============================================ */
.sticky-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border-bottom: 1px solid var(--border);
  transition: background 0.3s ease, box-shadow 0.3s ease;
}

[data-theme="dark"] .sticky-nav {
  background: rgba(11, 16, 32, 0.75);
}

.sticky-nav.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 24px;
}

/* Logo - 渐变文字 */
.logo {
  font-size: 1.9rem;
  font-weight: 900;
  letter-spacing: -1px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 50%, var(--primary-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  position: relative;
  flex-shrink: 0;
  transition: transform 0.3s ease;
}

.logo:hover {
  transform: scale(1.03);
}

.logo::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.logo:hover::after {
  transform: scaleX(1);
}

/* 导航链接 */
.nav-links {
  display: flex;
  gap: 32px;
  align-items: center;
}

.nav-links a {
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text);
  position: relative;
  padding: 8px 2px;
  transition: color 0.3s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

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

.nav-links a:hover::after {
  transform: scaleX(1);
}

/* 搜索框 - 毛玻璃 */
.search-box {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 8px 16px;
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  transition: all 0.3s ease;
  flex-shrink: 0;
}

.search-box:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.search-box input {
  width: 140px;
  font-size: 0.9rem;
  color: var(--text);
}

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

.icon-btn {
  font-size: 1.2rem;
  color: var(--muted);
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
}

.icon-btn:hover {
  color: var(--primary);
  background: rgba(79, 70, 229, 0.1);
}

/* 移动端菜单按钮 */
.mobile-menu {
  display: none;
  font-size: 1.5rem;
}

/* ============================================
   面包屑
   ============================================ */
.breadcrumb {
  padding: 16px 0;
  font-size: 0.85rem;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb span {
  color: var(--primary);
  font-weight: 600;
}

/* ============================================
   Banner 轮播 - 渐变霓虹
   ============================================ */
.banner {
  position: relative;
  border-radius: var(--radius-xl);
  overflow: hidden;
  margin: 16px 0 40px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--card-border);
  background: linear-gradient(145deg, #1e1b4b, #312e81, #4c1d95);
}

[data-theme="dark"] .banner {
  border-color: rgba(148, 163, 184, 0.2);
}

.slides {
  display: flex;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
  height: 340px;
}

.slide {
  min-width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px;
  position: relative;
  background: linear-gradient(145deg, rgba(30, 27, 75, 0.9), rgba(49, 46, 129, 0.9), rgba(76, 29, 149, 0.9));
}

.slide::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 30% 30%, rgba(129, 140, 248, 0.3) 0%, transparent 50%),
              radial-gradient(circle at 70% 70%, rgba(168, 85, 247, 0.2) 0%, transparent 50%);
  animation: bannerGlow 8s ease-in-out infinite alternate;
}

@keyframes bannerGlow {
  0% { transform: translate(0, 0) scale(1); }
  100% { transform: translate(20px, -20px) scale(1.1); }
}

.slide > div {
  position: relative;
  z-index: 1;
  animation: slideUp 0.8s ease both;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.slide h2 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  color: #fff;
  margin-bottom: 16px;
  letter-spacing: -1px;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.slide p {
  max-width: 600px;
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: rgba(255, 255, 255, 0.9);
  line-height: 1.6;
  margin: 0 auto;
}

.banner-btn {
  position: absolute;
  bottom: 20px;
  right: 20px;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: 50px;
  padding: 10px 20px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  font-size: 0.85rem;
  color: #fff;
  z-index: 2;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: 6px;
}

.banner-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-2px);
}

/* 轮播指示器 */
.banner-indicators {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  z-index: 2;
}

.banner-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.4);
  cursor: pointer;
  transition: all 0.3s ease;
}

.banner-dot.active {
  background: #fff;
  width: 24px;
  border-radius: 4px;
}

/* ============================================
   数字动画统计
   ============================================ */
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin: 40px 0;
}

.stat-item {
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: all 0.4s ease;
  position: relative;
  overflow: hidden;
}

.stat-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.stat-item:hover::before {
  transform: scaleX(1);
}

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

.stat-number {
  font-size: 2.8rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
  margin-bottom: 8px;
  font-variant-numeric: tabular-nums;
}

.stat-item > div:last-child {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 500;
}

/* ============================================
   通用区块标题
   ============================================ */
section h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 24px;
  position: relative;
  display: inline-block;
  letter-spacing: -0.5px;
}

section h2::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 4px;
}

/* ============================================
   卡片网格
   ============================================ */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
  margin: 32px 0;
}

.card {
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  box-shadow: var(--shadow-sm);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 100%;
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.03), rgba(168, 85, 247, 0.03));
  opacity: 0;
  transition: opacity 0.4s ease;
}

.card:hover {
  transform: translateY(-6px) scale(1.01);
  box-shadow: var(--shadow-md);
  border-color: rgba(79, 70, 229, 0.3);
}

.card:hover::before {
  opacity: 1;
}

.card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 12px;
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 8px;
}

.card h3 .emoji {
  font-size: 1.5rem;
}

.card p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.7;
  position: relative;
  z-index: 1;
}

/* ============================================
   品牌介绍区块
   ============================================ */
.reveal {
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 36px;
  margin: 24px 0;
  box-shadow: var(--shadow-sm);
  transition: all 0.4s ease;
}

.reveal:hover {
  box-shadow: var(--shadow-md);
}

.reveal p {
  margin-bottom: 16px;
  color: var(--muted);
  line-height: 1.8;
}

.reveal strong {
  color: var(--text);
  font-weight: 600;
}

/* ============================================
   文章列表
   ============================================ */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.article-item {
  padding: 20px 16px;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  transition: all 0.3s ease;
  border-radius: var(--radius-sm);
}

.article-item:last-child {
  border-bottom: none;
}

.article-item:hover {
  background: var(--card-bg);
  padding-left: 24px;
  border-radius: var(--radius-md);
}

.article-item a {
  color: var(--text);
  font-weight: 600;
  font-size: 0.98rem;
  transition: color 0.3s ease;
  position: relative;
}

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

.article-item a::after {
  content: '→';
  margin-left: 8px;
  opacity: 0;
  transform: translateX(-8px);
  transition: all 0.3s ease;
  display: inline-block;
}

.article-item a:hover::after {
  opacity: 1;
  transform: translateX(0);
}

.article-item time {
  color: var(--muted);
  font-size: 0.82rem;
  white-space: nowrap;
  background: var(--card-bg);
  padding: 4px 12px;
  border-radius: 20px;
  border: 1px solid var(--border);
  flex-shrink: 0;
}

/* ============================================
   FAQ 手风琴
   ============================================ */
.faq-item {
  margin-bottom: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  transition: all 0.3s ease;
}

.faq-item:hover {
  border-color: rgba(79, 70, 229, 0.3);
}

.faq-item.open {
  border-color: var(--primary);
  box-shadow: 0 4px 20px rgba(79, 70, 229, 0.1);
}

.faq-question {
  padding: 20px 24px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: transparent;
  font-size: 0.98rem;
  transition: all 0.3s ease;
  user-select: none;
}

.faq-question:hover {
  color: var(--primary);
}

.faq-question span {
  font-size: 1.4rem;
  font-weight: 400;
  color: var(--muted);
  transition: transform 0.3s ease;
  line-height: 1;
}

.faq-item.open .faq-question span {
  transform: rotate(45deg);
  color: var(--primary);
}

.faq-answer {
  padding: 0 24px 20px;
  color: var(--muted);
  line-height: 1.8;
  display: none;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

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

/* ============================================
   HowTo 教程步骤
   ============================================ */
.howto-steps {
  counter-reset: step;
  padding: 24px 0;
}

.howto-step {
  display: flex;
  gap: 20px;
  margin-bottom: 24px;
  padding: 20px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all 0.3s ease;
}

.howto-step:hover {
  border-color: rgba(79, 70, 229, 0.3);
  transform: translateX(4px);
}

.howto-step::before {
  counter-increment: step;
  content: counter(step);
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: white;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.1rem;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.howto-step div {
  flex: 1;
}

.howto-step strong {
  display: block;
  margin-bottom: 6px;
  font-size: 1.05rem;
}

.howto-step p {
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.7;
}

/* ============================================
   联系信息区块
   ============================================ */
#contact {
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-sm);
}

#contact p {
  margin-bottom: 12px;
  color: var(--muted);
  line-height: 1.8;
}

#contact strong {
  color: var(--text);
  font-weight: 600;
  min-width: 120px;
  display: inline-block;
}

/* ============================================
   页脚
   ============================================ */
footer {
  background: var(--card-bg);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border-top: 1px solid var(--border);
  padding: 48px 0 24px;
  margin-top: 60px;
  position: relative;
}

footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--primary-light), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 40px;
  margin-bottom: 40px;
}

.footer-grid h4 {
  margin-bottom: 16px;
  font-size: 1rem;
  font-weight: 700;
  position: relative;
  padding-bottom: 8px;
}

.footer-grid h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 24px;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
}

.footer-grid a {
  display: block;
  color: var(--muted);
  margin-bottom: 10px;
  font-size: 0.9rem;
  transition: all 0.3s ease;
  position: relative;
  padding-left: 0;
}

.footer-grid a:hover {
  color: var(--primary);
  padding-left: 8px;
}

.footer-grid a::before {
  content: '›';
  position: absolute;
  left: -8px;
  opacity: 0;
  transition: all 0.3s ease;
}

.footer-grid a:hover::before {
  opacity: 1;
  left: 0;
}

.copyright {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.8;
}

/* ============================================
   返回顶部按钮
   ============================================ */
#backTop {
  position: fixed;
  bottom: 40px;
  right: 40px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: white;
  border: none;
  border-radius: 50%;
  width: 52px;
  height: 52px;
  font-size: 1.4rem;
  cursor: pointer;
  box-shadow: 0 8px 24px rgba(79, 70, 229, 0.3);
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

#backTop.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#backTop:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 12px 32px rgba(79, 70, 229, 0.4);
}

#backTop:active {
  transform: scale(0.95);
}

/* ============================================
   滚动动画
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

/* 延迟动画辅助类 */
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* ============================================
   图片懒加载
   ============================================ */
.lazy-img {
  opacity: 0;
  transition: opacity 0.4s ease;
  filter: blur(8px);
}

.lazy-img.loaded {
  opacity: 1;
  filter: blur(0);
}

/* ============================================
   工具类
   ============================================ */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-gradient {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================
   响应式设计
   ============================================ */
@media (max-width: 1024px) {
  .container {
    padding: 0 20px;
  }

  .nav-links {
    gap: 20px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  /* 导航 */
  .nav-inner {
    height: 64px;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--card-bg);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    flex-direction: column;
    padding: 16px 24px;
    gap: 8px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    z-index: 100;
  }

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

  .nav-links a {
    padding: 12px 0;
    font-size: 1rem;
  }

  .search-box {
    display: none;
  }

  .mobile-menu {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
  }

  /* Banner */
  .slides {
    height: 280px;
  }

  .slide {
    padding: 24px;
  }

  .slide h2 {
    font-size: 1.8rem;
  }

  .slide p {
    font-size: 0.95rem;
  }

  .banner-btn {
    bottom: 12px;
    right: 12px;
    padding: 8px 16px;
    font-size: 0.8rem;
  }

  /* 统计 */
  .stats {
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
  }

  .stat-item {
    padding: 20px 12px;
  }

  .stat-number {
    font-size: 1.8rem;
  }

  /* 卡片 */
  .grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .card {
    padding: 24px 20px;
  }

  /* 文章列表 */
  .article-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 16px 12px;
  }

  .article-item:hover {
    padding-left: 16px;
  }

  .article-item time {
    align-self: flex-start;
  }

  /* FAQ */
  .faq-question {
    padding: 16px 18px;
    font-size: 0.92rem;
  }

  .faq-answer {
    padding: 0 18px 16px;
  }

  /* HowTo */
  .howto-step {
    padding: 16px;
    gap: 16px;
  }

  .howto-step::before {
    width: 32px;
    height: 32px;
    font-size: 1rem;
  }

  /* 联系 */
  #contact {
    padding: 24px;
  }

  #contact strong {
    min-width: 100px;
  }

  /* 页脚 */
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }

  /* 返回顶部 */
  #backTop {
    bottom: 24px;
    right: 24px;
    width: 44px;
    height: 44px;
    font-size: 1.2rem;
  }
}

@media (max-width: 480px) {
  .stats {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .stat-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    text-align: left;
  }

  .stat-number {
    font-size: 2rem;
    margin-bottom: 0;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .slide h2 {
    font-size: 1.5rem;
  }

  .slide p {
    font-size: 0.85rem;
  }
}

/* ============================================
   动画关键帧
   ============================================ */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes shimmer {
  0% { background-position: -200% center; }
  100% { background-position: 200% center; }
}

/* 性能优化 */
@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;
  }
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
  :root {
    --border: rgba(0, 0, 0, 0.2);
  }
}

/* 打印样式 */
@media print {
  .sticky-nav, .banner, #backTop, .banner-btn {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }

  .card, .reveal, .faq-item, #contact {
    background: #fff !important;
    border: 1px solid #ddd !important;
    box-shadow: none !important;
  }
}
```