:root {
  --primary: #1a2b3c;
  --primary-light: #2e4a6a;
  --accent: #ffb347;
  --accent-hover: #ff9f1a;
  --bg: #f8fafc;
  --bg-card: #ffffff;
  --text: #0b1e2e;
  --text-secondary: #5a6f7e;
  --text-muted: #6b7f8e;
  --border: #e9eef3;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 30px rgba(255, 179, 71, 0.15);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 30px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body.dark-mode {
  --bg: #0d1520;
  --bg-card: #16202e;
  --text: #d0e0f0;
  --text-secondary: #8fa5bb;
  --text-muted: #6b7f8e;
  --border: #1e2d3d;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.4);
  background: var(--bg);
  color: var(--text);
}

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

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

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

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

/* ========== HEADER ========== */
header {
  background: rgba(26, 43, 60, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  color: #fff;
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.15);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  transition: background var(--transition), box-shadow var(--transition);
}

body.dark-mode header {
  background: rgba(13, 21, 32, 0.9);
  border-bottom-color: rgba(255, 255, 255, 0.04);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.logo {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
  transition: transform var(--transition);
}

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

.logo span {
  color: #fff;
  font-weight: 400;
  font-size: 1rem;
  margin-left: 0;
  opacity: 0.85;
}

nav[aria-label="主导航"] ul {
  display: flex;
  list-style: none;
  gap: 20px;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}

nav[aria-label="主导航"] a {
  color: #e2e8f0;
  text-decoration: none;
  font-size: 0.95rem;
  transition: color var(--transition), transform var(--transition);
  position: relative;
  padding: 4px 0;
}

nav[aria-label="主导航"] a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transition: width var(--transition);
}

nav[aria-label="主导航"] a:hover {
  color: var(--accent);
}

nav[aria-label="主导航"] a:hover::after {
  width: 100%;
}

.search-box {
  display: flex;
  gap: 6px;
  align-items: center;
}

.search-box input {
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(255, 255, 255, 0.1);
  outline: none;
  font-size: 0.9rem;
  width: 180px;
  background: rgba(46, 64, 85, 0.6);
  color: #fff;
  transition: all var(--transition);
  font-family: var(--font);
}

.search-box input::placeholder {
  color: #a0b3c9;
}

.search-box input:focus {
  border-color: var(--accent);
  background: rgba(46, 64, 85, 0.9);
  box-shadow: 0 0 0 3px rgba(255, 179, 71, 0.15);
  width: 220px;
}

.search-box button {
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  border: none;
  border-radius: var(--radius-pill);
  padding: 8px 20px;
  font-weight: 600;
  color: var(--primary);
  cursor: pointer;
  font-size: 0.9rem;
  font-family: var(--font);
  transition: all var(--transition);
  white-space: nowrap;
}

.search-box button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(255, 179, 71, 0.4);
}

.search-box button:active {
  transform: translateY(0);
}

/* ========== BREADCRUMBS ========== */
.breadcrumbs {
  padding: 16px 0;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.breadcrumbs a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition);
}

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

.breadcrumbs span {
  color: var(--text-muted);
}

/* ========== TYPOGRAPHY ========== */
h1 {
  font-size: 2.4rem;
  margin: 10px 0 8px;
  color: var(--text);
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 1.8rem;
  margin-top: 48px;
  margin-bottom: 20px;
  color: var(--text);
  border-left: 6px solid var(--accent);
  padding-left: 18px;
  line-height: 1.3;
  font-weight: 700;
  letter-spacing: -0.01em;
  position: relative;
}

h2::after {
  content: '';
  position: absolute;
  left: 18px;
  bottom: -6px;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), transparent);
  border-radius: 3px;
}

h3 {
  font-size: 1.3rem;
  margin-top: 32px;
  margin-bottom: 12px;
  color: var(--primary-light);
  font-weight: 700;
  line-height: 1.4;
}

body.dark-mode h3 {
  color: #8fa5bb;
}

h4 {
  font-size: 1.1rem;
  margin-top: 20px;
  margin-bottom: 8px;
  color: var(--primary-light);
  font-weight: 600;
  line-height: 1.4;
}

body.dark-mode h4 {
  color: #8fa5bb;
}

p {
  margin: 0 0 16px;
  color: var(--text-secondary);
  line-height: 1.8;
}

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

ul, ol {
  padding-left: 24px;
  margin: 0 0 16px;
  color: var(--text-secondary);
}

li {
  margin-bottom: 8px;
  line-height: 1.7;
}

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

/* ========== BANNER ========== */
.banner-placeholder {
  background: linear-gradient(135deg, #1a2b3c 0%, #2e4a6a 40%, #3d5a80 70%, #2e4a6a 100%);
  background-size: 200% 200%;
  animation: gradientShift 12s ease infinite;
  border-radius: var(--radius-lg);
  padding: 56px 40px;
  color: #fff;
  margin: 20px 0 36px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  isolation: isolate;
}

.banner-placeholder::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255, 179, 71, 0.12) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}

.banner-placeholder::after {
  content: '';
  position: absolute;
  bottom: -40%;
  left: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 179, 71, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
  z-index: 0;
}

@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.banner-placeholder h2 {
  border: none;
  padding: 0;
  color: #fff;
  margin: 0 0 16px;
  font-size: 2.2rem;
  position: relative;
  z-index: 1;
}

.banner-placeholder h2::after {
  display: none;
}

.banner-placeholder h1 {
  color: #fff;
  position: relative;
  z-index: 1;
  font-size: 2.4rem;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.2);
}

.banner-placeholder p {
  max-width: 720px;
  color: rgba(255, 255, 255, 0.85);
  font-size: 1.1rem;
  position: relative;
  z-index: 1;
  line-height: 1.8;
}

.banner-placeholder .btn {
  position: relative;
  z-index: 1;
}

/* ========== STATS ========== */
.stats {
  display: flex;
  gap: 48px;
  margin: 28px 0;
  flex-wrap: wrap;
  position: relative;
  z-index: 1;
}

.stats > div {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1.1;
  letter-spacing: -0.02em;
  text-shadow: 0 2px 12px rgba(255, 179, 71, 0.3);
}

.stats > div > span:last-child {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 400;
}

/* ========== BUTTONS ========== */
.btn {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 10px 24px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
  transition: all var(--transition);
  border: none;
  cursor: pointer;
  font-family: var(--font);
  text-align: center;
  line-height: 1.5;
  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, 0.15), transparent);
  transition: left 0.5s ease;
}

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

.btn:hover {
  background: var(--accent);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(255, 179, 71, 0.35);
}

.btn:active {
  transform: translateY(0);
}

.btn-outline {
  background: transparent;
  border: 1.5px solid var(--primary);
  color: var(--primary);
}

body.dark-mode .btn-outline {
  border-color: var(--text-secondary);
  color: var(--text-secondary);
}

.btn-outline:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

body.dark-mode .btn-outline:hover {
  background: var(--accent);
  color: var(--primary);
  border-color: var(--accent);
}

.banner-placeholder .btn {
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  color: var(--primary);
  margin-top: 10px;
  box-shadow: 0 4px 20px rgba(255, 179, 71, 0.35);
}

.banner-placeholder .btn:hover {
  box-shadow: 0 8px 32px rgba(255, 179, 71, 0.5);
  transform: translateY(-3px);
}

/* ========== CARD GRID ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
  margin: 28px 0;
}

.card {
  background: rgba(255, 255, 255, 0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.6);
  transition: transform var(--transition), box-shadow var(--transition), border-color 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(--primary-light), var(--accent));
  background-size: 200% 100%;
  opacity: 0;
  transition: opacity var(--transition);
}

.card:hover::before {
  opacity: 1;
  animation: shimmer 2s linear infinite;
}

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

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: rgba(255, 179, 71, 0.2);
}

body.dark-mode .card {
  background: rgba(22, 32, 46, 0.75);
  border-color: rgba(255, 255, 255, 0.06);
}

body.dark-mode .card:hover {
  border-color: rgba(255, 179, 71, 0.15);
}

.card h4 {
  margin-top: 0;
  font-size: 1.1rem;
}

.card p {
  font-size: 0.92rem;
  margin-bottom: 16px;
  line-height: 1.7;
}

.card .btn {
  font-size: 0.85rem;
  padding: 8px 18px;
}

.meta {
  font-size: 0.83rem;
  color: var(--text-muted);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.meta::before {
  content: '📅';
  font-size: 0.8rem;
}

/* ========== FAQ ========== */
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 0;
  transition: background var(--transition);
  border-radius: var(--radius-sm);
  margin-bottom: 2px;
}

.faq-item:hover {
  background: rgba(255, 179, 71, 0.03);
}

.faq-question {
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
  padding: 16px 12px;
  font-size: 1rem;
  transition: color var(--transition);
  user-select: none;
  gap: 12px;
}

.faq-question::after {
  content: '▾';
  font-size: 1.1rem;
  color: var(--accent);
  transition: transform var(--transition);
  flex-shrink: 0;
}

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

.faq-answer {
  padding: 0 12px 16px 12px;
  color: var(--text-secondary);
  display: block;
  font-size: 0.95rem;
  line-height: 1.8;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ========== FOOTER ========== */
.footer {
  background: linear-gradient(180deg, #0b1e2e 0%, #0d1520 100%);
  color: #b0c4d9;
  padding: 48px 0 24px;
  margin-top: 80px;
  font-size: 0.9rem;
  position: relative;
  overflow: hidden;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 179, 71, 0.3), transparent);
}

.footer a {
  color: #b0c4d9;
  text-decoration: none;
  transition: color var(--transition), padding-left var(--transition);
  display: inline-block;
}

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

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 36px;
  margin-bottom: 36px;
}

.footer h4 {
  color: #fff;
  margin-bottom: 16px;
  font-size: 1.05rem;
  font-weight: 600;
  position: relative;
  padding-bottom: 10px;
}

.footer h4::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 28px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
}

.footer p {
  color: #b0c4d9;
  font-size: 0.88rem;
  line-height: 1.7;
  margin-bottom: 8px;
}

.footer ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer ul li {
  margin-bottom: 8px;
}

.footer ul li a {
  font-size: 0.88rem;
}

.footer > .container > p {
  text-align: center;
  border-top: 1px solid rgba(46, 64, 85, 0.6);
  padding-top: 24px;
  font-size: 0.83rem;
  color: #6b7f8e;
  margin-bottom: 0;
}

/* ========== BACK TO TOP ========== */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  color: #fff;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
  font-size: 1.4rem;
  z-index: 200;
  transition: all var(--transition);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: linear-gradient(135deg, var(--accent), var(--accent-hover));
  color: var(--primary);
  transform: translateY(-4px) scale(1.05);
  box-shadow: 0 8px 28px rgba(255, 179, 71, 0.4);
}

/* ========== UTILITY ========== */
.hidden {
  display: none !important;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
  white-space: nowrap;
}

/* ========== SCROLL ANIMATIONS ========== */
.fade-in-up {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ========== RESPONSIVE ========== */
@media (max-width: 1024px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }
  .banner-placeholder { padding: 44px 32px; }
  .banner-placeholder h1 { font-size: 2rem; }
  .banner-placeholder h2 { font-size: 1.8rem; }
  .stat-number { font-size: 2rem; }
  .stats { gap: 36px; }
}

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

  header { padding: 10px 0; }

  .header-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
  }

  .logo {
    font-size: 1.4rem;
    justify-content: center;
  }

  nav[aria-label="主导航"] ul {
    justify-content: center;
    gap: 12px;
  }

  nav[aria-label="主导航"] a {
    font-size: 0.85rem;
  }

  .search-box {
    justify-content: center;
  }

  .search-box input {
    width: 160px;
    font-size: 0.85rem;
  }

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

  h1 { font-size: 1.6rem; }
  h2 { font-size: 1.35rem; margin-top: 36px; padding-left: 14px; border-left-width: 4px; }
  h2::after { left: 14px; width: 40px; }
  h3 { font-size: 1.15rem; margin-top: 24px; }
  h4 { font-size: 1rem; }

  .banner-placeholder {
    padding: 36px 24px;
    border-radius: var(--radius-md);
    margin: 16px 0 28px;
  }

  .banner-placeholder h1 { font-size: 1.5rem; }
  .banner-placeholder h2 { font-size: 1.4rem; }
  .banner-placeholder p { font-size: 0.95rem; }

  .stats {
    gap: 24px;
    margin: 20px 0;
  }

  .stat-number { font-size: 1.6rem; }

  .card-grid {
    grid-template-columns: 1fr;
    gap: 16px;
    margin: 20px 0;
  }

  .card {
    padding: 20px;
    border-radius: var(--radius-sm);
  }

  .card:hover {
    transform: translateY(-3px);
  }

  .faq-question {
    font-size: 0.92rem;
    padding: 14px 10px;
  }

  .faq-answer {
    font-size: 0.88rem;
    padding: 0 10px 14px 10px;
  }

  .footer {
    padding: 36px 0 20px;
    margin-top: 60px;
  }

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

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
    font-size: 1.2rem;
  }

  .breadcrumbs {
    font-size: 0.82rem;
    padding: 12px 0;
  }
}

@media (max-width: 480px) {
  .container { padding: 0 12px; }

  .logo { font-size: 1.25rem; }
  .logo span { font-size: 0.85rem; }

  nav[aria-label="主导航"] ul {
    gap: 8px;
  }

  nav[aria-label="主导航"] a {
    font-size: 0.78rem;
  }

  .search-box input {
    width: 130px;
    padding: 7px 12px;
    font-size: 0.82rem;
  }

  .search-box input:focus {
    width: 150px;
  }

  .search-box button {
    padding: 7px 14px;
    font-size: 0.82rem;
  }

  h1 { font-size: 1.35rem; }
  h2 { font-size: 1.2rem; }
  h3 { font-size: 1.05rem; }

  .banner-placeholder {
    padding: 28px 18px;
  }

  .banner-placeholder h1 { font-size: 1.25rem; }
  .banner-placeholder p { font-size: 0.88rem; }

  .stats {
    gap: 16px;
  }

  .stat-number { font-size: 1.35rem; }
  .stats > div > span:last-child { font-size: 0.78rem; }

  .card {
    padding: 16px;
  }

  .card h4 { font-size: 0.95rem; }
  .card p { font-size: 0.85rem; }

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

  .btn {
    padding: 8px 18px;
    font-size: 0.85rem;
  }

  .faq-question {
    font-size: 0.85rem;
    padding: 12px 8px;
  }

  .faq-answer {
    font-size: 0.82rem;
    padding: 0 8px 12px 8px;
  }
}

/* ========== ACCESSIBILITY ========== */
@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;
  }

  .banner-placeholder {
    animation: none;
  }
}

/* ========== PRINT ========== */
@media print {
  header,
  .back-to-top,
  .search-box,
  .footer {
    display: none;
  }

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

  .card {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }

  .banner-placeholder {
    background: #eee;
    color: #000;
  }
}