```css
/* ===== 黑桃视频 全站样式表 ===== */
/* 设计语言：深蓝科技 + 活力渐变 + 毛玻璃质感 */

/* ---------- 设计令牌 ---------- */
:root {
  /* 主色板 - 深蓝科技风 */
  --primary: #2563eb;
  --primary-light: #3b82f6;
  --primary-dark: #1e3a8a;
  --accent-gradient: linear-gradient(135deg, #2563eb 0%, #7c3aed 50%, #db2777 100%);
  --accent-glow: 0 0 30px rgba(37, 99, 235, 0.3);

  /* 中性色 */
  --bg-body: #f0f4f8;
  --bg-surface: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.7);
  --bg-glass: rgba(255, 255, 255, 0.6);
  --bg-glass-strong: rgba(255, 255, 255, 0.8);
  --bg-footer: #0b1424;

  /* 文字 */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --text-inverse: #f8fafc;
  --text-footer: #94a3b8;

  /* 边框与阴影 */
  --border-color: rgba(148, 163, 184, 0.2);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.08);

  /* 毛玻璃 */
  --glass-blur: 12px;
  --glass-saturate: 180%;

  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;

  /* 间距 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  /* 字体 */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: "SF Pro Display", "Segoe UI", system-ui, sans-serif;
}

/* 暗黑模式 */
[data-theme="dark"] {
  --bg-body: #0b1322;
  --bg-surface: #111c2e;
  --bg-card: rgba(17, 28, 46, 0.7);
  --bg-glass: rgba(17, 28, 46, 0.6);
  --bg-glass-strong: rgba(17, 28, 46, 0.8);
  --bg-footer: #060d1a;

  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-inverse: #f1f5f9;
  --text-footer: #94a3b8;

  --border-color: rgba(148, 163, 184, 0.15);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);

  --primary: #3b82f6;
  --primary-light: #60a5fa;
  --primary-dark: #2563eb;
  --accent-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 50%, #ec4899 100%);
  --accent-glow: 0 0 40px rgba(59, 130, 246, 0.25);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background-color 0.4s ease, color 0.3s ease;
  overflow-x: hidden;
}

/* ---------- 通用容器 ---------- */
.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

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

/* ---------- 滚动条美化 ---------- */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

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

/* ---------- 导航栏 ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass-strong);
  backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
  border-bottom: 1px solid var(--border-color);
  transition: box-shadow 0.3s ease, background 0.3s ease;
}

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

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  font-size: 1.8rem;
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  text-decoration: none;
  letter-spacing: 0.5px;
  transition: transform 0.3s ease;
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo:hover {
  transform: scale(1.02);
}

.logo .logo-icon {
  font-size: 2rem;
  filter: drop-shadow(0 0 8px rgba(37, 99, 235, 0.4));
}

.logo span {
  background: none;
  -webkit-text-fill-color: var(--text-primary);
  font-weight: 500;
}

.nav-links {
  display: flex;
  gap: 32px;
  align-items: center;
  list-style: none;
}

.nav-links a:not(.theme-toggle) {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
  padding: 4px 0;
  transition: color 0.3s ease;
}

.nav-links a:not(.theme-toggle)::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: width 0.3s ease;
  border-radius: 2px;
}

.nav-links a:not(.theme-toggle):hover {
  color: var(--primary);
}

.nav-links a:not(.theme-toggle):hover::after {
  width: 100%;
}

/* 主题切换按钮 */
.theme-toggle {
  background: var(--bg-glass);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 8px 16px;
  border-radius: 50px;
  font-weight: 500;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.3s ease;
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  gap: 6px;
}

.theme-toggle:hover {
  background: var(--primary);
  color: #fff;
  border-color: transparent;
  transform: scale(1.05);
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
}

/* 移动端菜单按钮 */
.menu-icon {
  display: none;
  font-size: 1.8rem;
  cursor: pointer;
  color: var(--text-primary);
  background: none;
  border: none;
  padding: 4px;
  transition: transform 0.3s ease;
}

.menu-icon:hover {
  transform: scale(1.1);
}

/* 移动响应式导航 */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--bg-glass-strong);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    padding: 24px;
    box-shadow: var(--shadow-lg);
    border-bottom: 1px solid var(--border-color);
    gap: 16px;
    align-items: flex-start;
    animation: slideDown 0.3s ease forwards;
  }

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

  .nav-links a:not(.theme-toggle) {
    font-size: 1.1rem;
    width: 100%;
    padding: 8px 0;
  }

  .theme-toggle {
    margin-top: 8px;
  }

  .menu-icon {
    display: block;
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- 面包屑 ---------- */
.breadcrumb {
  font-size: 0.9rem;
  color: var(--text-muted);
  padding: 24px 0 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.breadcrumb a:hover {
  color: var(--primary-light);
}

/* ---------- Hero 区域 ---------- */
.hero {
  position: relative;
  padding: 80px 0 64px;
  overflow: hidden;
  background: var(--bg-body);
}

/* 渐变背景 */
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -20%;
  width: 80%;
  height: 80%;
  background: radial-gradient(circle at center, rgba(37, 99, 235, 0.15) 0%, transparent 70%);
  filter: blur(80px);
  pointer-events: none;
  animation: floatBlob 8s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  right: -10%;
  width: 60%;
  height: 60%;
  background: radial-gradient(circle at center, rgba(124, 58, 237, 0.15) 0%, transparent 70%);
  filter: blur(80px);
  pointer-events: none;
  animation: floatBlob 12s ease-in-out infinite reverse;
}

@keyframes floatBlob {
  0%, 100% {
    transform: translate(0, 0) scale(1);
  }
  50% {
    transform: translate(20px, -20px) scale(1.1);
  }
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 48px;
  align-items: center;
}

@media (max-width: 768px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    text-align: center;
  }
}

.hero h1 {
  font-family: var(--font-display);
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 24px;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.02em;
  animation: fadeInUp 0.8s ease forwards;
}

@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.2rem;
  }
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 540px;
  animation: fadeInUp 0.8s ease 0.2s forwards;
  opacity: 0;
}

@media (max-width: 768px) {
  .hero p {
    margin-left: auto;
    margin-right: auto;
    font-size: 1.05rem;
  }
}

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

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  animation: fadeInUp 0.8s ease 0.4s forwards;
  opacity: 0;
}

@media (max-width: 768px) {
  .hero-cta {
    justify-content: center;
  }
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-gradient);
  background-size: 200% auto;
  color: #ffffff;
  font-weight: 600;
  padding: 14px 32px;
  border-radius: 50px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.4s ease;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.3);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: left 0.5s ease;
}

.btn:hover {
  background-position: right center;
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(37, 99, 235, 0.4);
}

.btn:hover::before {
  left: 100%;
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary);
  color: var(--primary);
  box-shadow: none;
}

.btn-outline:hover {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 8px 24px rgba(37, 99, 235, 0.3);
}

/* 统计数字 */
.stats {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  margin-top: 48px;
  animation: fadeInUp 0.8s ease 0.6s forwards;
  opacity: 0;
}

@media (max-width: 768px) {
  .stats {
    justify-content: center;
    gap: 16px;
  }
}

.stat-item {
  background: var(--bg-glass);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  padding: 20px 28px;
  border-radius: var(--radius-md);
  text-align: center;
  border: 1px solid var(--border-color);
  transition: all 0.3s ease;
  flex: 1;
  min-width: 120px;
}

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

.stat-item strong {
  display: block;
  font-size: 2.4rem;
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.2;
}

.stat-item span {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

/* Hero SVG */
.hero svg {
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  transition: transform 0.4s ease;
}

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

/* ---------- 通用 Section ---------- */
.section {
  padding: 64px 0;
  position: relative;
}

.section-title {
  font-family: var(--font-display);
  font-size: 2.4rem;
  color: var(--text-primary);
  font-weight: 700;
  margin-bottom: 32px;
  position: relative;
  padding-left: 24px;
  line-height: 1.3;
}

.section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 6px;
  height: 100%;
  background: var(--accent-gradient);
  border-radius: 3px;
  box-shadow: var(--accent-glow);
}

@media (max-width: 768px) {
  .section-title {
    font-size: 1.8rem;
    padding-left: 16px;
  }
}

.section-sub {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 720px;
}

/* ---------- 网格布局 ---------- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

@media (max-width: 768px) {
  .grid-2, .grid-3 {
    grid-template-columns: 1fr;
    gap: 24px;
  }
}

/* ---------- 卡片 ---------- */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(var(--glass-blur)) saturate(var(--glass-saturate));
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(var(---glass-saturate));
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  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: 3px;
  background: var(--accent-gradient);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}

.card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.card:hover::before {
  transform: scaleX(1);
}

.card h3 {
  font-size: 1.4rem;
  color: var(--text-primary);
  margin-bottom: 16px;
  font-weight: 700;
}

.card p {
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.7;
}

.card strong {
  color: var(--text-primary);
}

.card a {
  color: var(--primary);
  font-weight: 500;
  text-decoration: none;
  transition: color 0.2s;
}

.card a:hover {
  color: var(--primary-light);
}

/* 卡片图标 */
.card-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.3);
}

/* ---------- 表格 ---------- */
table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  margin: 32px 0;
}

th, td {
  padding: 16px 24px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

th {
  background: var(--bg-glass);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

td {
  color: var(--text-secondary);
}

tr:last-child td {
  border-bottom: none;
}

tr {
  transition: background 0.2s ease;
}

tbody tr:hover {
  background: var(--bg-glass);
}

/* ---------- 文章列表 ---------- */
.article-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  margin-bottom: 8px;
  transition: all 0.3s ease;
  cursor: pointer;
}

.article-item:hover {
  background: var(--bg-glass);
  transform: translateX(8px);
  border-color: var(--primary);
}

.article-item h4 {
  font-size: 1.05rem;
  color: var(--text-primary);
  font-weight: 600;
  transition: color 0.2s;
}

.article-item:hover h4 {
  color: var(--primary);
}

.article-item span {
  color: var(--text-muted);
  font-size: 0.85rem;
  white-space: nowrap;
  margin-left: 16px;
}

@media (max-width: 768px) {
  .article-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding: 16px;
  }

  .article-item span {
    margin-left: 0;
  }
}

/* ---------- FAQ ---------- */
.faq-item {
  background: var(--bg-card);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-radius: var(--radius-md);
  margin-bottom: 16px;
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: all 0.3s ease;
}

.faq-item:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.faq-q {
  padding: 20px 28px;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: transparent;
  font-size: 1.05rem;
  transition: background 0.3s ease;
  user-select: none;
}

.faq-q:hover {
  background: var(--bg-glass);
}

.faq-q span {
  font-size: 1.2rem;
  transition: transform 0.3s ease;
  color: var(--primary);
}

.faq-item.active .faq-q span {
  transform: rotate(180deg);
}

.faq-a {
  padding: 0 28px 24px;
  color: var(--text-secondary);
  border-top: 1px solid transparent;
  padding-top: 16px;
  line-height: 1.8;
  display: none;
  animation: fadeIn 0.3s ease forwards;
}

.faq-item.active .faq-a {
  display: block;
  border-top-color: var(--border-color);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- HowTo ---------- */
.howto-steps {
  background: var(--bg-card);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  padding: 40px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
}

.howto-steps h3 {
  color: var(--text-primary);
  margin-bottom: 24px;
  font-size: 1.4rem;
}

.howto-steps ol {
  margin-left: 24px;
  color: var(--text-secondary);
  counter-reset: step;
}

.howto-steps li {
  margin-bottom: 16px;
  padding-left: 8px;
  position: relative;
  transition: color 0.2s;
}

.howto-steps li:hover {
  color: var(--primary);
}

.howto-steps li::marker {
  color: var(--primary);
  font-weight: bold;
}

.howto-steps p {
  margin-top: 24px;
  color: var(--text-secondary);
  background: var(--bg-glass);
  padding: 16px 20px;
  border-radius: var(--radius-sm);
  border-left: 4px solid var(--primary);
}

.howto-steps p strong {
  color: var(--text-primary);
}

/* ---------- 页脚 ---------- */
.footer {
  background-color: var(--bg-footer);
  color: var(--text-footer);
  padding: 64px 0 24px;
  margin-top: 64px;
  position: relative;
  overflow: hidden;
}

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

.footer h4 {
  color: #f8fafc;
  font-size: 1.2rem;
  margin-bottom: 20px;
  font-weight: 600;
  position: relative;
  padding-bottom: 12px;
}

.footer h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 32px;
  height: 2px;
  background: var(--primary);
  border-radius: 2px;
}

.footer a {
  color: var(--text-footer);
  text-decoration: none;
  display: block;
  margin-bottom: 12px;
  transition: all 0.3s ease;
  font-size: 0.95rem;
  position: relative;
  padding-left: 0;
}

.footer a:hover {
  color: #ffffff;
  padding-left: 8px;
}

.footer .grid-3 {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 32px;
}

.footer .grid-3 > div {
  flex: 1;
  min-width: 200px;
}

.footer .copyright {
  border-top: 1px solid rgba(148, 163, 184, 0.2);
  padding-top: 24px;
  margin-top: 48px;
  font-size: 0.9rem;
  color: var(--text-muted);
  text-align: center;
}

/* ---------- 返回顶部 ---------- */
.backtop {
  position: fixed;
  right: 24px;
  bottom: 24px;
  background: var(--accent-gradient);
  background-size: 200% auto;
  color: #fff;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.4);
  z-index: 999;
  border: none;
  transition: all 0.3s ease;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

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

.backtop:hover {
  background-position: right center;
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(37, 99, 235, 0.5);
}

/* ---------- 标签 ---------- */
.tag {
  display: inline-block;
  background: var(--accent-gradient);
  color: #fff;
  padding: 6px 16px;
  border-radius: 50px;
  font-size: 0.8rem;
  margin-right: 8px;
  font-weight: 500;
  transition: transform 0.2s ease;
}

.tag:hover {
  transform: scale(1.05);
}

/* ---------- SVG 样式 ---------- */
.svg-text {
  fill: #f8fafc;
  font-weight: bold;
}

.svg-bg {
  fill: #1a2634;
}

/* ---------- 搜索框 ---------- */
.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 50px;
  padding: 6px 6px 6px 20px;
  max-width: 360px;
  transition: all 0.3s ease;
  backdrop-filter: blur(var(--glass-blur));
}

.search-box:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.search-box input {
  border: none;
  background: transparent;
  color: var(--text-primary);
  font-size: 1rem;
  flex: 1;
  outline: none;
  padding: 8px 0;
}

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

.search-box button {
  background: var(--accent-gradient);
  color: white;
  border: none;
  padding: 10px 24px;
  border-radius: 50px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.3s ease;
}

.search-box button:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

/* ---------- 滚动动画 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.reveal-delay-1 {
  transition-delay: 0.1s;
}

.reveal-delay-2 {
  transition-delay: 0.2s;
}

.reveal-delay-3 {
  transition-delay: 0.3s;
}

/* ---------- 响应式调整 ---------- */
@media (max-width: 1024px) {
  .hero-grid {
    gap: 32px;
  }

  .hero h1 {
    font-size: 2.6rem;
  }

  .section {
    padding: 48px 0;
  }
}

@media (max-width: 768px) {
  html {
    scroll-padding-top: 64px;
  }

  .navbar .container {
    height: 64px;
  }

  .hero {
    padding: 48px 0 40px;
  }

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

  .hero p {
    font-size: 1rem;
  }

  .stats {
    margin-top: 32px;
  }

  .stat-item strong {
    font-size: 1.8rem;
  }

  .section-title {
    font-size: 1.6rem;
    margin-bottom: 24px;
  }

  .card {
    padding: 24px;
  }

  .footer {
    padding: 48px 0 16px;
  }

  .footer .grid-3 {
    flex-direction: column;
    gap: 32px;
  }

  .backtop {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
    font-size: 1.2rem;
  }
}

/* ---------- 打印优化 ---------- */
@media print {
  .navbar,
  .backtop,
  .theme-toggle,
  .menu-icon,
  .hero-cta {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  .card,
  .faq-item,
  .howto-steps {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
  }
}

/* ---------- 动画性能优化 ---------- */
@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;
  }
}

/* ---------- 暗色模式微调 ---------- */
[data-theme="dark"] .card {
  background: var(--bg-card);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .stat-item {
  background: var(--bg-glass);
}

[data-theme="dark"] .footer a:hover {
  color: var(--primary-light);
}

/* ---------- 工具类 ---------- */
.text-center {
  text-align: center;
}

.mt-1 { margin-top: var(--space-sm); }
.mt-2 { margin-top: var(--space-md); }
.mt-3 { margin-top: var(--space-lg); }
.mt-4 { margin-top: var(--space-xl); }
.mt-5 { margin-top: var(--space-2xl); }

.mb-1 { margin-bottom: var(--space-sm); }
.mb-2 { margin-bottom: var(--space-md); }
.mb-3 { margin-bottom: var(--space-lg); }
.mb-4 { margin-bottom: var(--space-xl); }
.mb-5 { margin-bottom: var(--space-2xl); }

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

/* ---------- 页面加载动画 ---------- */
@keyframes pageLoad {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

body {
  animation: pageLoad 0.5s ease forwards;
}
```