/* ============================================
   大模型 — 大模型 API 交易平台
   苹果风格 · 简约大气
   ============================================ */

:root {
  --bg: #fbfbfd;
  --bg-alt: #f5f5f7;
  --text: #1d1d1f;
  --text-secondary: #86868b;
  --text-tertiary: #6e6e73;
  --accent: #6C5CE7;
  --accent-light: #a29bfe;
  --gradient: linear-gradient(135deg, #6C5CE7, #00CEC9);
  --border: #d2d2d7;
  --card-bg: #ffffff;
  --radius: 16px;
  --radius-sm: 12px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   Navigation
   ============================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 12px 0;
  transition: background 0.3s ease, backdrop-filter 0.3s ease;
}

.nav.scrolled {
  background: rgba(251, 251, 253, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
}

.logo-text {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.3px;
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  transition: color 0.2s;
}

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

.nav-actions {
  display: flex;
  gap: 12px;
}

.btn-outline {
  display: inline-block;
  padding: 8px 20px;
  border: 1px solid var(--border);
  border-radius: 100px;
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.btn-primary {
  display: inline-block;
  padding: 8px 20px;
  background: var(--text);
  border: none;
  border-radius: 100px;
  color: white;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.btn-primary:hover {
  background: var(--accent);
}

.btn-large {
  padding: 14px 32px;
  font-size: 16px;
}

.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.mobile-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: 0.3s;
  border-radius: 2px;
}

/* ============================================
   Hero
   ============================================ */

.hero {
  position: relative;
  padding: 140px 0 100px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 900px;
  background: radial-gradient(ellipse at center, rgba(108, 92, 231, 0.06) 0%, transparent 60%);
  pointer-events: none;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  background: linear-gradient(135deg, rgba(108, 92, 231, 0.1), rgba(0, 206, 201, 0.1));
  border: 1px solid rgba(108, 92, 231, 0.2);
  border-radius: 100px;
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 24px;
}

.hero-title {
  font-size: 64px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -2px;
  margin-bottom: 24px;
}

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

.hero-subtitle {
  font-size: 20px;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 540px;
  margin-bottom: 40px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  margin-bottom: 80px;
}

.hero-stats {
  display: flex;
  gap: 48px;
}

.stat-item {
  text-align: center;
}

.stat-value {
  display: block;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 14px;
  color: var(--text-tertiary);
}

/* ============================================
   Models Marquee
   ============================================ */

.marquee-section {
  padding: 0;
  overflow: hidden;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  background: var(--bg-alt);
}

.marquee {
  overflow: hidden;
  padding: 16px 0;
}

.marquee-content {
  display: flex;
  gap: 8px;
  animation: marquee 30s linear infinite;
  white-space: nowrap;
}

.marquee-content span {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-tertiary);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.marquee-content .dot {
  color: var(--accent-light);
  opacity: 0.5;
}

@keyframes marquee {
  0% { transform: translateX(0); }
  100% { transform: translateX(-50%); }
}

/* ============================================
   Sections Common
   ============================================ */

section {
  padding: 120px 0;
}

.section-label {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -1px;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 480px;
  margin-bottom: 64px;
}

/* ============================================
   Products
   ============================================ */

.products {
  background: var(--bg);
}

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

.product-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: all 0.3s ease;
}

.product-card:hover {
  border-color: var(--accent-light);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(108, 92, 231, 0.06);
}

.card-icon {
  font-size: 32px;
  margin-bottom: 20px;
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
}

.product-card h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
}

.product-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 20px;
}

.card-link {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.2s;
}

.card-link:hover {
  opacity: 0.7;
}

/* ============================================
   Features
   ============================================ */

.features {
  background: var(--bg-alt);
}

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

.feature-card {
  padding: 32px;
}

.feature-number {
  font-size: 48px;
  font-weight: 800;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  opacity: 0.5;
  margin-bottom: 16px;
  line-height: 1;
}

.feature-card h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   Pricing
   ============================================ */

.pricing {
  background: var(--bg);
}

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

.pricing-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 40px;
  position: relative;
  transition: all 0.3s ease;
}

.pricing-card:hover {
  border-color: var(--accent-light);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(108, 92, 231, 0.06);
}

.pricing-card.featured {
  border-color: var(--accent);
  border-width: 2px;
}

.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient);
  color: white;
  font-size: 12px;
  font-weight: 600;
  padding: 4px 16px;
  border-radius: 100px;
}

.pricing-header {
  margin-bottom: 24px;
}

.pricing-header h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 4px;
}

.pricing-desc {
  font-size: 14px;
  color: var(--text-secondary);
}

.pricing-amount {
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
  gap: 2px;
}

.price {
  font-size: 44px;
  font-weight: 700;
  letter-spacing: -1px;
}

.currency {
  font-size: 20px;
  font-weight: 600;
}

.period {
  font-size: 14px;
  color: var(--text-secondary);
  margin-left: 4px;
}

.pricing-features {
  list-style: none;
  margin-bottom: 32px;
}

.pricing-features li {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 8px 0;
  border-bottom: 1px solid rgba(0,0,0,0.04);
}

.pricing-features li:last-child {
  border-bottom: none;
}

.btn-block {
  display: block;
  text-align: center;
}

/* ============================================
   Testimonial
   ============================================ */

.testimonial {
  background: var(--bg-alt);
  text-align: center;
}

.testimonial-content {
  max-width: 640px;
  margin: 0 auto;
}

.quote-icon {
  margin-bottom: 24px;
}

blockquote {
  font-size: 22px;
  font-weight: 500;
  line-height: 1.6;
  color: var(--text);
  margin-bottom: 32px;
}

.testimonial-author {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 48px;
}

.author-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 16px;
}

.author-name {
  font-size: 14px;
  font-weight: 600;
  text-align: left;
}

.author-role {
  font-size: 13px;
  color: var(--text-tertiary);
  text-align: left;
}

.testimonial-logos {
  display: flex;
  justify-content: center;
  gap: 32px;
  flex-wrap: wrap;
}

.testimonial-logos span {
  font-size: 13px;
  color: var(--text-tertiary);
  font-weight: 500;
  letter-spacing: 1px;
  text-transform: uppercase;
  opacity: 0.6;
}

/* ============================================
   CTA
   ============================================ */

.cta {
  background: var(--text);
  padding: 100px 0;
}

.cta-content {
  text-align: center;
}

.cta-content h2 {
  font-size: 44px;
  font-weight: 700;
  color: white;
  letter-spacing: -1px;
  margin-bottom: 16px;
}

.cta-content p {
  font-size: 18px;
  color: rgba(255, 255, 255, 0.6);
  margin-bottom: 40px;
}

.cta-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
}

.cta .btn-primary {
  background: white;
  color: var(--text);
}

.cta .btn-primary:hover {
  background: var(--accent);
  color: white;
}

.cta .btn-outline {
  border-color: rgba(255, 255, 255, 0.3);
  color: white;
}

.cta .btn-outline:hover {
  border-color: white;
}

/* ============================================
   Footer
   ============================================ */

.footer {
  background: var(--bg-alt);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-desc {
  font-size: 13px;
  color: var(--text-tertiary);
  margin-top: 12px;
  line-height: 1.7;
}

.footer-col h4 {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--text);
  margin-bottom: 16px;
}

.footer-col a {
  display: block;
  font-size: 13px;
  color: var(--text-tertiary);
  text-decoration: none;
  padding: 4px 0;
  transition: color 0.2s;
}

.footer-col a:hover {
  color: var(--text);
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border);
  text-align: center;
}

.footer-bottom p {
  font-size: 12px;
  color: var(--text-tertiary);
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 900px) {
  .hero-title {
    font-size: 40px;
  }

  .hero-subtitle {
    font-size: 17px;
  }

  .hero-stats {
    gap: 24px;
  }

  .section-title {
    font-size: 32px;
  }

  .product-grid,
  .features-grid,
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 640px) {
  .nav-links,
  .nav-actions {
    display: none;
  }

  .nav-links.active {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: rgba(251, 251, 253, 0.95);
    backdrop-filter: blur(20px);
    padding: 24px;
    gap: 20px;
  }

  .nav-actions.active {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 260px;
    left: 0;
    right: 0;
    padding: 0 24px;
    gap: 12px;
  }

  .mobile-toggle {
    display: flex;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero-title {
    font-size: 34px;
    letter-spacing: -1px;
  }

  .hero-actions {
    flex-direction: column;
    gap: 12px;
  }

  .hero-stats {
    flex-wrap: wrap;
    gap: 20px;
  }

  .stat-item {
    flex: 0 0 calc(50% - 10px);
  }

  .product-grid,
  .features-grid,
  .pricing-grid {
    grid-template-columns: 1fr;
  }

  .pricing-card.featured {
    order: -1;
  }

  .cta-actions {
    flex-direction: column;
    align-items: center;
  }

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