:root {
  --bg-body: #F4F7FC;
  --bg-card: #FFFFFF;
  --bg-nav: rgba(255, 255, 255, 0.82);
  --bg-footer: #0B1120;
  --bg-hero: #1E3A8A;
  --bg-hero-overlay: rgba(0, 0, 0, 0.45);
  --bg-glass: rgba(255, 255, 255, 0.55);
  --bg-glass-strong: rgba(255, 255, 255, 0.75);
  --text-primary: #17202A;
  --text-secondary: #1F2937;
  --text-muted: #475569;
  --text-light: #64748B;
  --text-inverse: #F8FAFC;
  --text-inverse-muted: #CBD5E1;
  --text-heading: #0F172A;
  --text-link: #1D4ED8;
  --text-link-hover: #1E40AF;
  --text-button: #FFFFFF;
  --bg-button: #1D4ED8;
  --bg-button-hover: #1E3A8A;
  --border-color: #E2E8F0;
  --border-glass: rgba(255, 255, 255, 0.35);
  --gradient-hero: linear-gradient(135deg, #1E3A8A 0%, #2563EB 45%, #0F172A 100%);
  --gradient-accent: linear-gradient(135deg, #1D4ED8 0%, #7C3AED 100%);
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.10);
  --shadow-lg: 0 18px 48px rgba(15, 23, 42, 0.16);
  --shadow-glow: 0 8px 32px rgba(29, 78, 216, 0.35);
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 28px;
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

body.dark-mode {
  --bg-body: #0B1120;
  --bg-card: #151F33;
  --bg-nav: rgba(15, 23, 42, 0.82);
  --bg-footer: #020617;
  --bg-hero: #0B1120;
  --bg-hero-overlay: rgba(2, 6, 23, 0.72);
  --bg-glass: rgba(30, 41, 59, 0.55);
  --bg-glass-strong: rgba(30, 41, 59, 0.78);
  --text-primary: #E5E7EB;
  --text-secondary: #E2E8F0;
  --text-muted: #CBD5E1;
  --text-light: #94A3B8;
  --text-inverse: #FFFFFF;
  --text-inverse-muted: #94A3B8;
  --text-heading: #F8FAFC;
  --text-link: #60A5FA;
  --text-link-hover: #93C5FD;
  --text-button: #FFFFFF;
  --bg-button: #2563EB;
  --bg-button-hover: #3B82F6;
  --border-color: #263449;
  --border-glass: rgba(148, 163, 184, 0.22);
  --gradient-hero: linear-gradient(135deg, #0B1120 0%, #1E3A8A 55%, #020617 100%);
  --gradient-accent: linear-gradient(135deg, #2563EB 0%, #7C3AED 100%);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.55);
  --shadow-lg: 0 18px 48px rgba(0, 0, 0, 0.65);
  --shadow-glow: 0 8px 32px rgba(37, 99, 235, 0.4);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.75;
  transition: background-color 0.35s ease, color 0.35s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-heading);
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 0.6em;
  transition: color 0.35s ease;
  letter-spacing: -0.01em;
}

h1 { font-size: 2.2rem; letter-spacing: -0.025em; }
h2 { font-size: 1.85rem; margin-top: 1.4em; }
h3 { font-size: 1.35rem; margin-top: 1.1em; }
h4 { font-size: 1.15rem; margin-top: 1em; }

p {
  margin-bottom: 1.1em;
  color: var(--text-primary);
  transition: color 0.35s ease;
}

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

a:hover {
  color: var(--text-link-hover);
  text-decoration: underline;
}

ul, ol {
  margin-bottom: 1.1em;
  padding-left: 1.5em;
}

li {
  margin-bottom: 0.45em;
  color: var(--text-primary);
}

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

strong { color: var(--text-heading); }

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ============ 导航栏 ============ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-nav);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  backdrop-filter: saturate(180%) blur(18px);
  box-shadow: var(--shadow-sm);
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.35s ease, box-shadow 0.35s ease, border-color 0.35s ease;
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-heading);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.logo:hover { text-decoration: none; color: var(--text-heading); }

.logo svg {
  width: 36px;
  height: 36px;
  border-radius: 9px;
  box-shadow: var(--shadow-glow);
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.logo:hover svg { transform: rotate(-8deg) scale(1.06); }

.nav-links {
  display: flex;
  gap: 22px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  position: relative;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 6px 0;
  transition: color 0.2s ease;
}

.nav-links a::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  border-radius: 2px;
  background: var(--gradient-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-links a:hover {
  color: var(--text-link);
  text-decoration: none;
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.theme-toggle {
  background: var(--bg-glass);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-glass);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-primary);
  transition: background-color 0.3s ease, border-color 0.3s ease, color 0.3s ease, transform 0.3s ease;
}

.theme-toggle:hover {
  background: var(--bg-card);
  transform: rotate(20deg) scale(1.05);
}

.mobile-menu-btn {
  display: none;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: 10px;
  font-size: 1.35rem;
  line-height: 1;
  cursor: pointer;
  color: var(--text-primary);
  padding: 8px 12px;
  transition: background-color 0.3s ease, transform 0.2s ease;
}

.mobile-menu-btn:hover { transform: scale(1.05); }

.mobile-menu {
  display: none;
  background-color: var(--bg-nav);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
  border-top: 1px solid var(--border-color);
  padding: 10px 20px 18px;
  animation: slideDown 0.3s ease;
}

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

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

.mobile-menu a {
  display: block;
  padding: 12px 4px;
  font-size: 1rem;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border-color);
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.mobile-menu a:hover {
  color: var(--text-link);
  padding-left: 10px;
  text-decoration: none;
}

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

/* ============ Hero ============ */
.hero {
  position: relative;
  background: var(--gradient-hero);
  color: var(--text-inverse);
  padding: 90px 0 80px;
  overflow: hidden;
  isolation: isolate;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--bg-hero-overlay);
  z-index: 1;
  transition: background 0.35s ease;
}

.hero::after {
  content: '';
  position: absolute;
  width: 620px;
  height: 620px;
  right: -180px;
  top: -220px;
  background: radial-gradient(circle, rgba(124, 58, 237, 0.5) 0%, rgba(124, 58, 237, 0) 70%);
  border-radius: 50%;
  z-index: 1;
  pointer-events: none;
  animation: floatGlow 12s ease-in-out infinite alternate;
}

@keyframes floatGlow {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to { transform: translate3d(-40px, 40px, 0) scale(1.15); }
}

.hero .container {
  position: relative;
  z-index: 2;
}

.hero h1 {
  color: #FFFFFF;
  font-size: 2.7rem;
  margin-bottom: 18px;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.45);
  animation: heroRise 0.8s cubic-bezier(0.22, 1, 0.36, 1) both;
}

.hero p {
  color: #E2E8F0;
  font-size: 1.15rem;
  max-width: 760px;
  margin-bottom: 28px;
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.35);
  animation: heroRise 0.8s 0.12s cubic-bezier(0.22, 1, 0.36, 1) both;
}

@keyframes heroRise {
  from { opacity: 0; transform: translateY(28px); }
  to { opacity: 1; transform: translateY(0); }
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 34px;
  animation: heroRise 0.8s 0.22s cubic-bezier(0.22, 1, 0.36, 1) both;
}

.hero-badge {
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 50px;
  padding: 7px 20px;
  font-size: 0.9rem;
  color: #FFFFFF;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  transition: background 0.25s ease, transform 0.25s ease, border-color 0.25s ease;
}

.hero-badge:hover {
  background: rgba(255, 255, 255, 0.26);
  border-color: rgba(255, 255, 255, 0.5);
  transform: translateY(-2px);
}

.hero-cta {
  display: inline-block;
  background: var(--bg-button);
  color: var(--text-button);
  padding: 15px 40px;
  border-radius: 50px;
  font-size: 1.05rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.25s ease, transform 0.25s ease, box-shadow 0.25s ease;
  box-shadow: var(--shadow-glow);
  animation: heroRise 0.8s 0.32s cubic-bezier(0.22, 1, 0.36, 1) both;
}

.hero-cta:hover {
  background: var(--bg-button-hover);
  color: #FFFFFF;
  text-decoration: none;
  transform: translateY(-3px) scale(1.02);
  box-shadow: 0 12px 40px rgba(29, 78, 216, 0.5);
}

/* ============ 面包屑 ============ */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  color: var(--text-muted);
  padding: 18px 0;
  list-style: none;
  margin: 0;
}

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

.breadcrumb li + li::before {
  content: '›';
  margin-right: 6px;
  color: var(--text-muted);
}

/* ============ 轮播 ============ */
.carousel {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  margin: 24px 0 40px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  transition: background-color 0.35s ease, border-color 0.35s ease;
}

.carousel-track {
  display: flex;
  transition: transform 0.55s cubic-bezier(0.4, 0, 0.2, 1);
}

.carousel-slide {
  min-width: 100%;
  padding: 52px 44px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  background: var(--bg-card);
  transition: background-color 0.35s ease;
}

.carousel-slide h3 {
  font-size: 1.6rem;
  color: var(--text-heading);
  margin-bottom: 12px;
}

.carousel-slide p {
  color: var(--text-primary);
  font-size: 1rem;
  max-width: 640px;
}

.carousel-dots {
  display: flex;
  justify-content: center;
  gap: 10px;
  padding: 16px 0 20px;
  background: var(--bg-card);
  transition: background-color 0.35s ease;
}

.carousel-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--border-color);
  border: none;
  cursor: pointer;
  padding: 0;
  transition: background 0.3s ease, transform 0.3s ease, width 0.3s ease;
}

.carousel-dot:hover { background: var(--text-link); }

.carousel-dot.active {
  background: var(--bg-button);
  transform: scale(1.15);
  width: 26px;
  border-radius: 6px;
}

/* ============ 卡片 ============ */
.card {
  position: relative;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 30px 26px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: background-color 0.35s ease, border-color 0.35s ease, box-shadow 0.3s ease, transform 0.3s ease;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--gradient-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

.card h3 {
  margin-top: 0;
  font-size: 1.22rem;
}

.card p {
  color: var(--text-primary);
  font-size: 0.95rem;
  margin-bottom: 0;
}

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

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

/* ============ 章节 ============ */
.section {
  padding: 64px 0;
  position: relative;
}

.section-alt {
  background: var(--bg-card);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.35s ease, border-color 0.35s ease;
}

.section-title {
  text-align: center;
  margin-bottom: 12px;
  font-size: 1.95rem;
  color: var(--text-heading);
  position: relative;
  padding-bottom: 14px;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 56px;
  height: 4px;
  border-radius: 4px;
  background: var(--gradient-accent);
}

.section-subtitle {
  text-align: center;
  color: var(--text-muted);
  font-size: 1rem;
  max-width: 720px;
  margin: 0 auto 44px;
}

/* ============ 数据统计 ============ */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.stat-item {
  padding: 24px 12px;
  border-radius: var(--radius-md);
  background: var(--bg-glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-glass);
  transition: transform 0.3s ease, box-shadow 0.3s ease, background-color 0.35s ease;
}

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

.stat-item .stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: var(--text-link);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.stat-item .stat-label {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-top: 6px;
}

/* ============ 列表 ============ */
.feature-list {
  list-style: none;
  padding: 0;
}

.feature-list li {
  position: relative;
  padding-left: 30px;
  margin-bottom: 12px;
  color: var(--text-primary);
  transition: transform 0.2s ease;
}

.feature-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  top: 0;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: #FFFFFF;
  background: var(--gradient-accent);
  border-radius: 50%;
  line-height: 1;
}

.feature-list li:hover { transform: translateX(4px); }

.feature-list li a { color: var(--text-link); }

/* ============ 表格 ============ */
.data-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin: 24px 0;
  font-size: 0.95rem;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.data-table th {
  background: var(--gradient-accent);
  color: #FFFFFF;
  padding: 14px 18px;
  text-align: left;
  font-weight: 600;
  font-size: 0.92rem;
  letter-spacing: 0.02em;
}

.data-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-primary);
  transition: background-color 0.2s ease, color 0.35s ease;
}

.data-table tbody tr:last-child td { border-bottom: none; }

.data-table tbody tr:nth-child(even) td { background: var(--bg-body); }

.data-table tbody tr {
  transition: background-color 0.2s ease;
}

.data-table tbody tr:hover td {
  background: var(--bg-glass);
}

/* ============ FAQ ============ */
.faq-item {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  background: var(--bg-card);
  transition: border-color 0.3s ease, box-shadow 0.3s ease, background-color 0.35s ease;
}

.faq-item:hover {
  border-color: var(--text-link);
  box-shadow: var(--shadow-sm);
}

.faq-item.open {
  border-color: var(--text-link);
  box-shadow: var(--shadow-md);
}

.faq-question {
  width: 100%;
  text-align: left;
  padding: 18px 24px;
  background: var(--bg-card);
  border: none;
  font-size: 1.03rem;
  font-weight: 600;
  font-family: inherit;
  color: var(--text-heading);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  transition: background-color 0.25s ease, color 0.35s ease;
}

.faq-question:hover { background: var(--bg-body); }

.faq-question .faq-icon {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 400;
  color: #FFFFFF;
  background: var(--gradient-accent);
  border-radius: 50%;
  transition: transform 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.faq-item.open .faq-icon { transform: rotate(135deg); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.45s cubic-bezier(0.4, 0, 0.2, 1), padding 0.35s ease;
  padding: 0 24px;
  background: var(--bg-card);
}

.faq-item.open .faq-answer {
  max-height: 800px;
  padding: 0 24px 22px;
}

.faq-answer p {
  color: var(--text-primary);
  font-size: 0.95rem;
  margin-bottom: 0;
}

/* ============ 文章卡片 ============ */
.article-card {
  position: relative;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 24px;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: box-shadow 0.3s ease, transform 0.3s ease, border-color 0.3s ease, background-color 0.35s ease;
}

.article-card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-md);
  background: var(--gradient-accent);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
  mix-blend-mode: overlay;
}

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

.article-card .article-date {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 8px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.article-card .article-date::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gradient-accent);
}

.article-card h4 {
  font-size: 1.05rem;
  margin-bottom: 8px;
  color: var(--text-heading);
  transition: color 0.2s ease;
}

.article-card:hover h4 { color: var(--text-link); }

.article-card p {
  font-size: 0.9rem;
  color: var(--text-primary);
  flex: 1;
  margin-bottom: 14px;
}

.article-card .read-more {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-link);
  align-self: flex-start;
  transition: transform 0.25s ease, color 0.2s ease;
}

.article-card .read-more:hover {
  text-decoration: none;
  transform: translateX(4px);
}

/* ============ 按钮 ============ */
.btn {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 50px;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: background 0.25s ease, color 0.25s ease, transform 0.25s ease, box-shadow 0.25s ease;
}

.btn-primary {
  background: var(--bg-button);
  color: var(--text-button);
  box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
  background: var(--bg-button-hover);
  color: #FFFFFF;
  text-decoration: none;
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(29, 78, 216, 0.45);
}

.btn-outline {
  background: transparent;
  color: var(--text-link);
  border: 2px solid var(--text-link);
}

.btn-outline:hover {
  background: var(--text-link);
  color: #FFFFFF;
  text-decoration: none;
  transform: translateY(-2px);
}

/* ============ 表单 ============ */
.form-group { margin-bottom: 18px; }

.form-group label {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 7px;
  transition: color 0.35s ease;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 13px 16px;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  font-size: 0.95rem;
  font-family: inherit;
  background: var(--bg-card);
  color: var(--text-primary);
  transition: border-color 0.25s ease, box-shadow 0.25s ease, background-color 0.35s ease, color 0.35s ease;
}

.form-group textarea { resize: vertical; min-height: 120px; }

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--text-link);
  box-shadow: 0 0 0 4px rgba(29, 78, 216, 0.15);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: var(--text-muted);
  opacity: 1;
}

/* ============ 搜索框 ============ */
.search-box {
  display: flex;
  gap: 10px;
  max-width: 520px;
  margin: 0 auto;
  padding: 8px;
  background: var(--bg-glass);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border: 1px solid var(--border-glass);
  border-radius: 50px;
  box-shadow: var(--shadow-sm);
  transition: background-color 0.35s ease, border-color 0.35s ease, box-shadow 0.3s ease;
}

.search-box:focus-within {
  box-shadow: var(--shadow-md);
  border-color: var(--text-link);
}

.search-box input {
  flex: 1;
  padding: 10px 20px;
  border: none;
  border-radius: 50px;
  font-size: 0.95rem;
  font-family: inherit;
  background: transparent;
  color: var(--text-primary);
  transition: color 0.35s ease;
}

.search-box input:focus { outline: none; }

.search-box button {
  padding: 10px 26px;
  border-radius: 50px;
  background: var(--bg-button);
  color: var(--text-button);
  border: none;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.25s ease, transform 0.2s ease;
}

.search-box button:hover {
  background: var(--bg-button-hover);
  transform: scale(1.03);
}

/* ============ 返回顶部 ============ */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-accent);
  color: var(--text-button);
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 999;
  transition: transform 0.25s ease, box-shadow 0.25s ease, opacity 0.3s ease;
}

.back-to-top.visible {
  display: flex;
  animation: popIn 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes popIn {
  from { opacity: 0; transform: scale(0.6); }
  to { opacity: 1; transform: scale(1); }
}

.back-to-top:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: var(--shadow-lg);
}

/* ============ 滚动动画 ============ */
.fade-in {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.65s cubic-bezier(0.22, 1, 0.36, 1), transform 0.65s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: opacity, transform;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============ 元信息 ============ */
.meta-info {
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
  margin-top: 20px;
  transition: color 0.35s ease, border-color 0.35s ease;
}

.meta-info span { margin-right: 16px; }

/* ============ Footer ============ */
.footer {
  background: var(--bg-footer);
  color: var(--text-inverse-muted);
  padding: 56px 0 26px;
  position: relative;
  overflow: hidden;
  transition: background-color 0.35s ease, color 0.35s ease;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--gradient-accent);
}

.footer h4 {
  color: #FFFFFF;
  font-size: 1rem;
  margin-bottom: 16px;
  letter-spacing: 0.02em;
}

.footer a {
  color: var(--text-inverse-muted);
  font-size: 0.88rem;
  display: block;
  margin-bottom: 9px;
  transition: color 0.2s ease, transform 0.2s ease;
}

.footer a:hover {
  color: #FFFFFF;
  text-decoration: none;
  transform: translateX(3px);
}

.footer p {
  color: var(--text-inverse-muted);
  font-size: 0.85rem;
  line-height: 1.75;
  margin-bottom: 8px;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  margin-top: 40px;
  padding-top: 22px;
  text-align: center;
  color: var(--text-inverse-muted);
  font-size: 0.82rem;
}

.footer-bottom p { margin-bottom: 6px; }

.footer-bottom a {
  display: inline;
  margin: 0;
  color: #CBD5E1;
}

.footer-bottom a:hover { color: #FFFFFF; }

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 36px;
}

/* ============ 标签 ============ */
.tag {
  display: inline-block;
  background: var(--bg-glass);
  color: var(--text-secondary);
  border: 1px solid var(--border-glass);
  border-radius: 50px;
  padding: 5px 16px;
  font-size: 0.82rem;
  margin: 0 6px 6px 0;
  transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, transform 0.2s ease;
}

.tag:hover {
  transform: translateY(-2px);
  border-color: var(--text-link);
  color: var(--text-link);
}

/* ============ 文本工具类 ============ */
.text-primary { color: var(--text-primary) !important; }
.text-secondary { color: var(--text-secondary) !important; }
.text-muted { color: var(--text-muted) !important; }
.text-heading { color: var(--text-heading) !important; }
.text-inverse { color: var(--text-inverse) !important; }

/* ============ 交互增强 ============ */
button, .btn, .hero-cta, .search-box button {
  color: var(--text-button);
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--text-link);
  outline-offset: 2px;
  border-radius: 4px;
}

button:disabled, .btn:disabled {
  opacity: 0.65;
  cursor: not-allowed;
  transform: none !important;
}

::selection {
  background: var(--text-link);
  color: #FFFFFF;
}

/* ============ 懒加载 ============ */
.lazy-load {
  opacity: 0;
  transition: opacity 0.55s ease;
}

.lazy-load.loaded { opacity: 1; }

/* ============ 暗色模式补充 ============ */
body.dark-mode .section-alt {
  background: #101A2C;
}

body.dark-mode .data-table tbody tr:nth-child(even) td {
  background: #101A2C;
}

body.dark-mode .data-table tbody tr:hover td {
  background: rgba(37, 99, 235, 0.12);
}

body.dark-mode .faq-question:hover {
  background: #101A2C;
}

body.dark-mode .hero-badge {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.22);
}

body.dark-mode .hero-badge:hover {
  background: rgba(255, 255, 255, 0.18);
}

body.dark-mode .stat-item {
  background: rgba(30, 41, 59, 0.6);
  border-color: rgba(148, 163, 184, 0.18);
}

body.dark-mode .search-box {
  background: rgba(30, 41, 59, 0.6);
  border-color: rgba(148, 163, 184, 0.18);
}

body.dark-mode .theme-toggle:hover {
  background: #1E293B;
}

body.dark-mode .card::before,
body.dark-mode .article-card::after {
  opacity: 0.9;
}

/* ============ 响应式 ============ */
@media (max-width: 992px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .hero h1 { font-size: 2.2rem; }
  .nav-links { gap: 16px; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-menu-btn { display: block; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .hero { padding: 56px 0 48px; }
  .hero h1 { font-size: 1.75rem; }
  .hero p { font-size: 1rem; }
  .hero::after { width: 380px; height: 380px; right: -140px; top: -160px; }
  .section { padding: 44px 0; }
  .section-title { font-size: 1.5rem; }
  .section-subtitle { margin-bottom: 32px; }
  .stats-row { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .stat-item .stat-number { font-size: 1.9rem; }
  .carousel-slide { padding: 34px 24px; }
  .carousel-slide h3 { font-size: 1.3rem; }
  .back-to-top { bottom: 20px; right: 20px; width: 44px; height: 44px; }
  .search-box { flex-direction: column; border-radius: var(--radius-lg); padding: 10px; }
  .search-box input { text-align: center; }
  .search-box button { width: 100%; }
  .data-table { font-size: 0.86rem; }
  .data-table th, .data-table td { padding: 10px 12px; }
  .faq-question { padding: 16px 18px; font-size: 0.98rem; }
  .faq-answer { padding: 0 18px; }
  .faq-item.open .faq-answer { padding: 0 18px 18px; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }
  .stats-row { grid-template-columns: 1fr; }
  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.3rem; }
  .hero h1 { font-size: 1.55rem; }
  .hero-cta { width: 100%; text-align: center; padding: 14px 24px; }
  .hero-badge { font-size: 0.82rem; padding: 6px 14px; }
  .section-title { font-size: 1.35rem; }
  .card { padding: 24px 20px; }
  .article-card { padding: 20px; }
  .stat-item .stat-number { font-size: 1.7rem; }
  .logo span { font-size: 1.15rem; }
}

/* ============ 减少动画偏好 ============ */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .fade-in { opacity: 1; transform: none; }
}

/* ============ 打印样式 ============ */
@media print {
  .navbar, .back-to-top, .hero-cta, .search-box, .theme-toggle, .mobile-menu-btn {
    display: none !important;
  }
  body { background: #FFFFFF; color: #000000; }
  .card, .article-card, .faq-item { box-shadow: none; border: 1px solid #CCCCCC; }
  .hero { background: #1E3A8A !important; -webkit-print-color-adjust: exact; print-color-adjust: exact; }
}