html { scroll-behavior: smooth; }
* { margin: 0; padding: 0; box-sizing: border-box; user-select: none; -webkit-tap-highlight-color: transparent; }
.email-link, .btn-copy-email, .logo, .nav-link { user-select: text; }
img, video, iframe { user-drag: none; pointer-events: auto; }

:root {
  --bg-page: #f6f8fc;
  --bg-card: #ffffff;
  --text-primary: #0f1d33;
  --text-secondary: #4a5875;
  --text-tertiary: #8494ad;
  --border-soft: rgba(15,29,51,0.06);
  --border-medium: rgba(15,29,51,0.10);
  --accent: #3556d8;
  --accent-deep: #5b3fd9;
  --accent-soft: #eef2ff;
  --accent-hover: #dde5ff;
  --accent-gradient: linear-gradient(135deg, #3556d8 0%, #5b3fd9 100%);
  --shadow-xs: 0 1px 2px rgba(15,29,51,0.04);
  --shadow-sm: 0 2px 8px rgba(15,29,51,0.05), 0 1px 2px rgba(15,29,51,0.04);
  --shadow-md: 0 6px 24px rgba(15,29,51,0.07), 0 2px 6px rgba(15,29,51,0.04);
  --shadow-lg: 0 16px 48px rgba(15,29,51,0.10), 0 4px 12px rgba(15,29,51,0.05);
  --radius: 16px;
  --radius-lg: 20px;
  --nav-h: 68px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg-page);
  color: var(--text-primary);
  line-height: 1.65;
  overflow-x: hidden;
  padding: 0 0 2rem 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
::selection { background: rgba(53,86,216,0.18); color: var(--text-primary); }
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #c8d1e0; border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: #a9b5c8; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 2rem; }

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 9999;
  background: #ffffff;
  border-bottom: 1px solid var(--border-soft);
}
.site-header.scrolled {
  box-shadow: 0 6px 24px rgba(15,29,51,0.06);
}
.nav-progress {
  position: absolute;
  top: 0; left: 0;
  height: 2px;
  width: 0;
  background: var(--accent-gradient);
  transition: width 0.1s linear;
  z-index: 10;
}
.nav-bar {
  height: var(--nav-h);
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  position: relative;
}
.brand {
  font-weight: 800;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
}
.nav-desktop {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  flex: 1;
  justify-content: center;
  min-width: 0;
}
.nav-desktop .nav-link {
  display: inline-block;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  padding: 0.5rem 0.85rem;
  border-radius: 8px;
  white-space: nowrap;
  transition: color 0.2s ease, background 0.2s ease;
  position: relative;
}
.nav-desktop .nav-link:hover {
  color: var(--accent);
  background: rgba(53,86,216,0.05);
}
.nav-desktop .nav-link.active { color: var(--accent); }
.nav-desktop .nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 2px; left: 50%;
  transform: translateX(-50%);
  width: 16px; height: 2px;
  border-radius: 2px;
  background: var(--accent-gradient);
}
.nav-tools {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}
.lang-btn {
  background: var(--accent-soft);
  border: none;
  border-radius: 40px;
  padding: 0.4rem 0.9rem;
  font-weight: 600;
  font-size: 0.75rem;
  color: var(--accent);
  cursor: pointer;
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  white-space: nowrap;
  transition: background 0.2s ease;
  -webkit-appearance: none;
  appearance: none;
  flex-shrink: 0;
}
.lang-btn:hover { background: var(--accent-hover); }
.contact-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: transparent;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.83rem;
  padding: 0.45rem 0.9rem;
  border-radius: 40px;
  border: 1px solid var(--border-medium);
  text-decoration: none;
  white-space: nowrap;
  transition: all 0.25s ease;
  flex-shrink: 0;
}
.contact-link i { font-size: 0.78rem; color: var(--accent); }
.contact-link:hover {
  color: var(--accent);
  border-color: rgba(53,86,216,0.3);
  background: rgba(53,86,216,0.04);
}
.menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  padding: 0;
  border-radius: 8px;
  -webkit-appearance: none;
  appearance: none;
  flex-shrink: 0;
}
.menu-btn:active { background: rgba(53,86,216,0.08); }
.menu-btn i {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.2s ease;
  font-style: normal;
}
.menu-btn.open i:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-btn.open i:nth-child(2) { opacity: 0; }
.menu-btn.open i:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
.nav-mobile {
  display: none;
  background: #ffffff;
  border-top: 1px solid var(--border-soft);
  padding: 0.5rem 1.15rem calc(1.25rem + env(safe-area-inset-bottom, 0px));
  max-height: 75vh;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
.nav-mobile.open { display: block; }
.nav-mobile .nav-link {
  display: block;
  width: 100%;
  padding: 0.9rem 1rem;
  border-radius: 10px;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 1rem;
  transition: background 0.2s ease, color 0.2s ease;
}
.nav-mobile .nav-link:hover,
.nav-mobile .nav-link.active {
  background: var(--accent-soft);
  color: var(--accent);
}
.nav-mobile .nav-mobile-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  margin-top: 0.75rem;
  padding: 0.85rem 1rem;
  border-radius: 12px;
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid rgba(53,86,216,0.1);
}
.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(15,29,51,0.35);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
  z-index: 9998;
}
.nav-overlay.active { opacity: 1; visibility: visible; }

body { padding-top: var(--nav-h); }
section[id] { scroll-margin-top: 90px; }

.hero {
  padding: 4rem 0 5rem;
  text-align: center;
}
.hero h1 {
  font-size: clamp(2.4rem, 5.5vw, 3.8rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.15;
  margin-bottom: 1.25rem;
}
.hero h1 span {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero .subhead {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2.25rem;
  line-height: 1.7;
}
.btn-group { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.75rem; }

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  background: var(--accent-gradient);
  color: #fff;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.75rem 2rem;
  border-radius: 50px;
  text-decoration: none;
  transition: all 0.28s ease;
  box-shadow: 0 4px 16px rgba(53,86,216,0.22);
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 26px rgba(53,86,216,0.32);
}
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  background: #fff;
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.75rem 2rem;
  border-radius: 50px;
  text-decoration: none;
  border: 1px solid var(--border-medium);
  transition: all 0.28s ease;
  box-shadow: var(--shadow-xs);
}
.btn-secondary:hover {
  border-color: rgba(53,86,216,0.35);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

section { padding: 3.5rem 0; }
#china { padding-top: 4rem; }
#video { padding-top: 5rem; }
#faq { padding-top: 5rem; }

.section-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.section-title {
  font-size: clamp(1.65rem, 2.8vw, 2.15rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.85rem;
  color: var(--text-primary);
}
.section-sub {
  color: var(--text-secondary);
  max-width: 620px;
  margin-bottom: 2.5rem;
  font-size: 1rem;
  line-height: 1.7;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}
.card-item {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.85rem 1.6rem;
  border: 1px solid var(--border-soft);
  box-shadow: var(--shadow-sm);
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}
.card-item::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 2px;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity 0.35s ease;
}
.card-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.card-item:hover::before { opacity: 1; }
.card-item h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.card-item p {
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.65;
}

.carousel-container {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-soft);
  padding: 1.5rem 0 1.25rem;
}
.carousel-viewport {
  overflow: hidden;
  width: 100%;
}
.carousel-track {
  display: flex;
  transition: transform 0.45s ease;
  gap: 1.25rem;
  padding: 0 1.5rem;
  will-change: transform;
}
.carousel-slide {
  flex: 0 0 calc(33.333% - 0.85rem);
  min-width: 0;
  background: #fbfcfe;
  border-radius: var(--radius);
  padding: 1.5rem 1.3rem;
  border: 1px solid var(--border-soft);
  transition: all 0.3s ease;
}
.carousel-slide:hover {
  background: #fff;
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.carousel-slide h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 0.45rem;
}
.carousel-slide p {
  color: var(--text-secondary);
  font-size: 0.88rem;
  line-height: 1.65;
}
.carousel-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1.35rem;
  padding: 0 1.5rem;
}
.carousel-dots {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex: 1;
}
.carousel-dots span {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: #d5dce8;
  cursor: pointer;
  transition: all 0.3s ease;
}
.carousel-dots span.active {
  background: var(--accent-gradient);
  width: 22px;
  border-radius: 6px;
}
.carousel-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.carousel-btn {
  width: 38px; height: 38px;
  border-radius: 50%;
  background: #fff;
  border: 1px solid var(--border-medium);
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  transition: all 0.25s ease;
  -webkit-appearance: none;
  appearance: none;
}
.carousel-btn:hover:not(:disabled) {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
  transform: translateY(-1px);
}
.carousel-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.video-section {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-soft);
  margin: 1.75rem 0;
}
.video-section .video-wrapper {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  border-radius: 12px;
  background: #e8edf5;
}
.video-section .video-wrapper iframe {
  position: absolute; top: 0; left: 0;
  width: 100%; height: 100%; border: 0;
}

.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 3rem;
  align-items: center;
  margin: 2.5rem 0;
}
.about-text {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.85;
}
.about-text p + p { margin-top: 0.9rem; }
.about-text strong { color: var(--text-primary); font-weight: 600; }
.about-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: flex-end;
}
.stat-item {
  text-align: center;
  background: var(--bg-card);
  padding: 1.5rem 1.6rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-soft);
  flex: 1 1 100px;
  transition: all 0.3s ease;
}
.stat-number {
  font-size: 2.1rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}
.stat-label {
  color: var(--text-tertiary);
  font-size: 0.78rem;
  font-weight: 500;
  margin-top: 0.35rem;
}

.media-matrix-grid {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}
.media-matrix-item {
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  background: var(--bg-card);
  padding: 1.2rem 1.1rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-soft);
  transition: all 0.3s ease;
  min-width: 84px;
  cursor: pointer;
}
.media-matrix-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(53,86,216,0.2);
}
.media-matrix-item .icon {
  font-size: 2.35rem;
  line-height: 1;
}

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.faq-item {
  background: var(--bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-soft);
  overflow: hidden;
  transition: all 0.3s ease;
}
.faq-item[open] {
  border-color: rgba(53,86,216,0.18);
  box-shadow: var(--shadow-md);
}
.faq-item summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 1.15rem 1.4rem;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.98rem;
  color: var(--text-primary);
  list-style: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '\f078';
  font-family: 'Font Awesome 6 Free';
  font-weight: 900;
  font-size: 0.75rem;
  color: var(--accent);
  transition: transform 0.3s ease;
  flex-shrink: 0;
}
.faq-item[open] summary::after { transform: rotate(180deg); }
.faq-answer {
  padding: 0 1.4rem 1.35rem;
  color: var(--text-secondary);
  line-height: 1.75;
  font-size: 0.92rem;
}

.contact-box {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 2.75rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-soft);
  max-width: 620px;
  margin: 2rem auto;
  position: relative;
  overflow: hidden;
}
.contact-box::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent-gradient);
}
.contact-box .email-link {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
  background: var(--accent-soft);
  padding: 0.65rem 1.9rem;
  border-radius: 50px;
  transition: all 0.28s ease;
  max-width: 100%;
}
.contact-box .email-link:hover { background: var(--accent-hover); }
.btn-copy-email {
  background: var(--accent-soft);
  border: 1px solid rgba(53,86,216,0.08);
  border-radius: 50px;
  padding: 0.65rem 1.4rem;
  font-weight: 500;
  font-size: 0.88rem;
  color: var(--accent);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-family: inherit;
  -webkit-appearance: none;
  appearance: none;
}
.btn-copy-email:hover { background: var(--accent-hover); }

.footer {
  border-top: 1px solid var(--border-soft);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 0.8rem;
  margin-top: 4rem;
}

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

@media (max-width: 960px) {
  .nav-desktop { display: none; }
  .menu-btn { display: flex; }
  .contact-link { display: none; }
}

@media (max-width: 768px) {
  .container { padding: 0 1.15rem; }
  .nav-bar { padding: 0 1rem; height: 60px; }
  :root { --nav-h: 60px; }
  body { padding-top: 60px; }
  .brand { font-size: 1.15rem; }
  .lang-btn { padding: 0.35rem 0.7rem; font-size: 0.7rem; }
  .menu-btn { width: 36px; height: 36px; }
  .menu-btn i { width: 20px; }

  .hero { padding: 2.5rem 0 3.25rem; }
  .hero h1 { font-size: 2rem; }
  .hero .subhead { font-size: 0.95rem; margin-bottom: 1.75rem; }
  .btn-primary, .btn-secondary { padding: 0.7rem 1.5rem; font-size: 0.88rem; }

  section { padding: 2.75rem 0; }
  #china { padding-top: 3rem; }
  #video { padding-top: 4rem; }
  #faq { padding-top: 4rem; }
  .section-title { font-size: 1.45rem; }
  .section-sub { font-size: 0.92rem; margin-bottom: 1.85rem; }

  .card-grid { grid-template-columns: 1fr; gap: 1rem; }
  .card-item { padding: 1.5rem 1.25rem; }

  .carousel-container { padding: 1.15rem 0 1rem; }
  .carousel-track { gap: 0.9rem; padding: 0 1.1rem; }
  .carousel-slide { flex: 0 0 calc(50% - 0.45rem); padding: 1.2rem 1.05rem; }
  .carousel-slide h3 { font-size: 0.96rem; }
  .carousel-slide p { font-size: 0.82rem; }
  .carousel-controls { padding: 0 1.1rem; }
  .carousel-btn { width: 34px; height: 34px; font-size: 0.72rem; }

  .video-section { padding: 0.9rem; margin: 1.25rem 0; }

  .about-grid { grid-template-columns: 1fr; gap: 1.75rem; margin: 1.75rem 0; }
  .about-text { font-size: 0.95rem; }
  .about-stats { justify-content: center; gap: 0.75rem; }
  .stat-item { padding: 1.15rem 1rem; }
  .stat-number { font-size: 1.65rem; }

  .media-matrix-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.6rem;
    max-width: 480px;
    margin-left: auto;
    margin-right: auto;
  }
  .media-matrix-item { min-width: 0; padding: 0.85rem 0.4rem; }
  .media-matrix-item .icon { font-size: 1.85rem; }

  .contact-box { padding: 2rem 1.25rem; margin: 1.5rem auto; }
  .contact-box .email-link { font-size: 0.9rem; padding: 0.6rem 1.2rem; }
  .btn-copy-email { padding: 0.6rem 1.1rem; font-size: 0.82rem; }

  .faq-item summary { padding: 1rem 1.15rem; font-size: 0.92rem; }
  .faq-answer { padding: 0 1.15rem 1.15rem; font-size: 0.88rem; }

  .footer { margin-top: 3rem; padding: 1.75rem 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 1rem; }
  .nav-bar { padding: 0 0.9rem; }
  .brand { font-size: 1.05rem; }

  .hero { padding: 2rem 0 2.75rem; }
  .hero h1 { font-size: 1.7rem; }
  .hero .subhead { font-size: 0.9rem; }
  .btn-group { flex-direction: column; align-items: stretch; }
  .btn-primary, .btn-secondary { width: 100%; justify-content: center; }

  .section-title { font-size: 1.3rem; }
  #video { padding-top: 3.5rem; }
  #faq { padding-top: 3.5rem; }

  .carousel-slide { flex: 0 0 calc(100% - 0.15rem); padding: 1.15rem 1rem; }
  .carousel-track { padding: 0 0.95rem; gap: 0.75rem; }
  .carousel-controls { padding: 0 0.95rem; }

  .about-stats { flex-wrap: nowrap; gap: 0.5rem; }
  .stat-item { padding: 0.95rem 0.5rem; }
  .stat-number { font-size: 1.35rem; }
  .stat-label { font-size: 0.68rem; }

  .media-matrix-grid { grid-template-columns: repeat(4, 1fr); gap: 0.45rem; }
  .media-matrix-item { padding: 0.7rem 0.3rem; }
  .media-matrix-item .icon { font-size: 1.5rem; }

  .contact-box { padding: 1.75rem 1rem; }
  .contact-box .email-link { font-size: 0.85rem; padding: 0.55rem 1rem; width: 100%; justify-content: center; }
  .btn-copy-email { width: 100%; justify-content: center; font-size: 0.8rem; }
}