:root {
  --bg: #0a0c10;
  --bg-elev: #12161e;
  --bg-card: #181e28;
  --bg-glass: rgba(18, 22, 30, 0.72);
  --text-primary: #f0f4fa;
  --text-secondary: #b0b8c5;
  --text-muted: #7a8494;
  --accent: #3b82f6;
  --accent-glow: #60a5fa;
  --accent-soft: #1e3a5f;
  --accent-alt: #a78bfa;
  --accent-alt-soft: rgba(167, 139, 250, 0.12);
  --border: #252c3a;
  --border-light: rgba(255, 255, 255, 0.06);
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.6);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.7);
  --shadow-glow: 0 0 40px rgba(59, 130, 246, 0.18);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 8px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

[data-theme="light"] {
  --bg: #f7f9fc;
  --bg-elev: #ffffff;
  --bg-card: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.78);
  --text-primary: #0b1219;
  --text-secondary: #3e4a5a;
  --text-muted: #6b7a8d;
  --accent: #2563eb;
  --accent-glow: #3b82f6;
  --accent-soft: #dbeafe;
  --accent-alt: #7c3aed;
  --accent-alt-soft: rgba(124, 58, 237, 0.08);
  --border: #e2e8f0;
  --border-light: rgba(0, 0, 0, 0.04);
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.1);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.7;
  transition: background var(--transition), color var(--transition);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding-top: 72px;
  overflow-x: hidden;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

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

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

button {
  font-family: inherit;
}

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

/* ===== 导航栏 ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.navbar.scrolled {
  box-shadow: var(--shadow);
  border-bottom-color: transparent;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  flex-shrink: 0;
  transition: transform var(--transition);
}

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

.logo svg {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
  transition: transform var(--transition-slow);
}

.logo:hover svg {
  transform: rotate(12deg);
}

.logo span {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 4px 0;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-alt));
  border-radius: 2px;
  transition: width var(--transition);
}

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

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-shrink: 0;
}

.theme-toggle,
.menu-toggle {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 10px;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--transition);
  flex-shrink: 0;
}

.theme-toggle:hover,
.menu-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.2);
}

.theme-toggle svg,
.menu-toggle svg {
  transition: transform var(--transition-slow);
}

.theme-toggle:hover svg {
  transform: rotate(20deg);
}

.menu-toggle {
  display: none;
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0 12px;
  height: 40px;
  width: 200px;
  transition: border var(--transition), width var(--transition), box-shadow var(--transition);
}

.search-box:focus-within {
  border-color: var(--accent);
  width: 240px;
  box-shadow: 0 0 0 3px var(--accent-alt-soft);
}

.search-box input {
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 0.88rem;
  width: 100%;
  font-family: inherit;
}

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

.search-box svg {
  width: 18px;
  height: 18px;
  color: var(--text-muted);
  flex-shrink: 0;
}

/* ===== 移动菜单 ===== */
.mobile-menu {
  display: none;
  position: fixed;
  top: 72px;
  left: 0;
  width: 100%;
  background: var(--bg-glass);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border);
  padding: 20px 24px;
  z-index: 999;
  flex-direction: column;
  gap: 0;
  box-shadow: var(--shadow-lg);
  animation: slideDown 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.mobile-menu.open {
  display: flex;
}

.mobile-menu a {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
  transition: color var(--transition), padding-left var(--transition);
}

.mobile-menu a:hover {
  color: var(--accent);
  padding-left: 8px;
}

.mobile-menu a:last-child {
  border-bottom: none;
}

/* ===== 面包屑 ===== */
.breadcrumb {
  padding: 16px 0 8px;
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

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

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

.breadcrumb span {
  color: var(--text-secondary);
}

/* ===== 首屏 Hero ===== */
.hero {
  position: relative;
  padding: 48px 0 56px;
  overflow: hidden;
  border-bottom: 1px solid var(--border);
}

.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  background: radial-gradient(ellipse at 20% 30%, rgba(59, 130, 246, 0.12) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 70%, rgba(139, 92, 246, 0.10) 0%, transparent 55%);
  pointer-events: none;
  animation: heroPulse 8s ease-in-out infinite alternate;
}

@keyframes heroPulse {
  0% {
    opacity: 0.7;
    transform: scale(1);
  }
  100% {
    opacity: 1;
    transform: scale(1.08);
  }
}

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

.hero-text h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.hero-text h1 .highlight {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-text p {
  font-size: 1.08rem;
  color: var(--text-secondary);
  max-width: 520px;
  margin-bottom: 28px;
}

.hero-cta {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  font-family: inherit;
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.15), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

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

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #fff;
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 12px 32px rgba(59, 130, 246, 0.45);
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-primary);
}

.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(59, 130, 246, 0.15);
}

/* ===== Banner 轮播 ===== */
.banner-carousel {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition), box-shadow var(--transition);
}

.banner-carousel:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.banner-slides {
  display: flex;
  transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.banner-slide {
  min-width: 100%;
  position: relative;
}

.banner-slide svg {
  width: 100%;
  height: auto;
  display: block;
}

.banner-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 24px;
  background: linear-gradient(transparent, rgba(0, 0, 0, 0.78));
  color: #fff;
}

.banner-caption h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.banner-caption p {
  font-size: 0.85rem;
  opacity: 0.85;
}

.banner-dots {
  position: absolute;
  bottom: 12px;
  right: 16px;
  display: flex;
  gap: 8px;
}

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

.banner-dot:hover {
  background: rgba(255, 255, 255, 0.7);
}

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

/* ===== 数字动画 ===== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 40px;
}

.stat-item {
  text-align: center;
  padding: 20px 12px;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.stat-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-alt));
  transform: scaleX(0);
  transition: transform var(--transition);
}

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

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

.stat-number {
  font-size: 1.8rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* ===== 通用区块 ===== */
.section {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}

.section:last-of-type {
  border-bottom: none;
}

.section-header {
  margin-bottom: 40px;
}

.section-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 10px;
  position: relative;
  display: inline-block;
}

.section-header h2::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 48px;
  height: 3px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-alt));
}

.section-header p {
  color: var(--text-secondary);
  max-width: 720px;
  margin-top: 14px;
}

.section-header h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 24px 0 8px;
  color: var(--text-primary);
}

.section-header h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 16px 0 6px;
  color: var(--text-secondary);
}

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

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

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

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

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

.card h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 10px;
}

.card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.card-icon {
  width: 44px;
  height: 44px;
  margin-bottom: 16px;
  color: var(--accent);
  transition: transform var(--transition), color var(--transition);
}

.card:hover .card-icon {
  transform: scale(1.12) rotate(-4deg);
  color: var(--accent-alt);
}

/* ===== 文章列表 ===== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.article-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--accent-alt-soft), transparent 60%);
  opacity: 0;
  transition: opacity var(--transition);
  pointer-events: none;
}

.article-card:hover {
  border-color: var(--accent);
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.article-card:hover::after {
  opacity: 1;
}

.article-card .meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 8px;
  display: flex;
  gap: 12px;
  position: relative;
  z-index: 1;
}

.article-card h3 {
  font-size: 1.02rem;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.4;
  position: relative;
  z-index: 1;
  transition: color var(--transition);
}

.article-card:hover h3 {
  color: var(--accent);
}

.article-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  flex: 1;
  margin-bottom: 14px;
  position: relative;
  z-index: 1;
}

.article-card .read-more {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  position: relative;
  z-index: 1;
  transition: gap var(--transition), color var(--transition);
}

.article-card:hover .read-more {
  gap: 10px;
  color: var(--accent-alt);
}

/* ===== FAQ ===== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

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

.faq-item:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.1);
}

.faq-item.active {
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.15);
}

.faq-question {
  width: 100%;
  background: transparent;
  border: none;
  padding: 18px 22px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  font-family: inherit;
  transition: color var(--transition), background var(--transition);
}

.faq-question:hover {
  color: var(--accent);
  background: var(--accent-alt-soft);
}

.faq-question svg {
  width: 18px;
  height: 18px;
  transition: transform var(--transition);
  flex-shrink: 0;
}

.faq-item.active .faq-question svg {
  transform: rotate(180deg);
  color: var(--accent);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 22px;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.faq-item.active .faq-answer {
  max-height: 400px;
  padding: 0 22px 20px;
}

/* ===== HowTo ===== */
.howto-step {
  display: flex;
  gap: 20px;
  margin-bottom: 28px;
  padding: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.howto-step::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(180deg, var(--accent), var(--accent-alt));
  transform: scaleY(0);
  transform-origin: top;
  transition: transform var(--transition);
}

.howto-step:hover {
  border-color: var(--accent);
  transform: translateX(4px);
  box-shadow: var(--shadow-glow);
}

.howto-step:hover::before {
  transform: scaleY(1);
}

.howto-num {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  flex-shrink: 0;
  transition: all var(--transition);
}

.howto-step:hover .howto-num {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #fff;
  transform: scale(1.1);
}

.howto-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.howto-content p {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* ===== 联系区块 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}

.contact-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.contact-item:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

.contact-item svg {
  width: 22px;
  height: 22px;
  color: var(--accent);
  flex-shrink: 0;
  margin-top: 3px;
  transition: transform var(--transition), color var(--transition);
}

.contact-item:hover svg {
  transform: scale(1.15);
  color: var(--accent-alt);
}

.contact-item h4 {
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.contact-item p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* ===== 页脚 ===== */
.footer {
  background: var(--bg-elev);
  border-top: 1px solid var(--border);
  padding: 48px 0 28px;
  position: relative;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), var(--accent-alt), transparent);
  opacity: 0.5;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 36px;
}

.footer-brand p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 12px;
  max-width: 320px;
}

.footer h4 {
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 16px;
  position: relative;
  display: inline-block;
}

.footer h4::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 20px;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: color var(--transition), padding-left var(--transition);
  display: inline-block;
}

.footer-links a:hover {
  color: var(--accent);
  padding-left: 4px;
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ===== 返回顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  z-index: 900;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #fff;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.4);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 10px 30px rgba(59, 130, 246, 0.55);
}

/* ===== 滚动动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
  will-change: opacity, transform;
}

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

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .hero-content {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .stats-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .nav-links {
    gap: 20px;
  }

  .nav-links a {
    font-size: 0.86rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .menu-toggle {
    display: flex;
  }

  .search-box {
    width: 140px;
  }

  .search-box:focus-within {
    width: 180px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .hero {
    padding: 32px 0 40px;
  }

  .section {
    padding: 44px 0;
  }

  .banner-caption {
    padding: 16px;
  }

  .banner-caption h3 {
    font-size: 0.95rem;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .article-grid {
    grid-template-columns: 1fr;
  }

  .contact-grid {
    grid-template-columns: 1fr;
  }

  .howto-step {
    padding: 18px;
    gap: 14px;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

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

  .stats-row {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }

  .stat-number {
    font-size: 1.4rem;
  }

  .stat-item {
    padding: 16px 8px;
  }

  .hero-cta {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }

  .search-box {
    display: none;
  }

  .hero-text h1 {
    font-size: 1.7rem;
  }

  .hero-text p {
    font-size: 0.95rem;
  }

  .section-header h2 {
    font-size: 1.4rem;
  }

  .card {
    padding: 22px 18px;
  }

  .article-card {
    padding: 20px;
  }

  .faq-question {
    padding: 16px 18px;
    font-size: 0.9rem;
  }

  .faq-answer {
    padding: 0 18px;
    font-size: 0.85rem;
  }

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

  .howto-step {
    flex-direction: column;
    gap: 12px;
  }

  .howto-num {
    width: 34px;
    height: 34px;
    font-size: 0.9rem;
  }

  .footer {
    padding: 36px 0 24px;
  }
}

/* ===== 无障碍与动效偏好 ===== */
@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;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ===== 打印样式 ===== */
@media print {
  .navbar,
  .mobile-menu,
  .back-to-top,
  .banner-carousel,
  .hero-bg {
    display: none !important;
  }

  body {
    padding-top: 0;
    background: #fff;
    color: #000;
  }

  .section {
    border-bottom: none;
    page-break-inside: avoid;
  }
}