/* ============================================
   Notion-Style Homepage for 云梦智能
   文档化、黑白克制、知识库表达
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f7f6f3;
  --bg-tertiary: #f1f1ef;
  --text-primary: #37352f;
  --text-secondary: #6b6b6b;
  --text-tertiary: #9b9b9b;
  --border-light: #e9e9e7;
  --border-medium: #d4d4d2;
  --accent: #2383e2;
  --accent-hover: #1b6ec2;
  --accent-light: #e8f2fc;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.08);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
  --max-width: 1120px;
  --nav-height: 56px;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

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

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-light);
  z-index: 1000;
  transition: box-shadow 0.2s ease;
}

.nav.scrolled {
  box-shadow: var(--shadow-sm);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 15px;
  color: var(--text-primary);
  text-decoration: none;
}

.nav-logo:hover {
  text-decoration: none;
}

.nav-logo img {
  height: 28px;
  width: auto;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.nav-links a {
  padding: 6px 12px;
  font-size: 14px;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
  text-decoration: none;
}

.nav-links a:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.nav-dropdown {
  position: relative;
}

.nav-dropdown-toggle {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 6px 12px;
  font-size: 14px;
  color: var(--text-secondary);
  background: none;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.15s ease;
  font-family: var(--font-sans);
}

.nav-dropdown-toggle:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.nav-dropdown-toggle svg {
  width: 12px;
  height: 12px;
  transition: transform 0.15s ease;
}

.nav-dropdown.open .nav-dropdown-toggle svg {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 180px;
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: 6px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: all 0.15s ease;
  list-style: none;
}

.nav-dropdown.open .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-dropdown-menu a {
  display: block;
  padding: 8px 12px;
  font-size: 14px;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  text-decoration: none;
}

.nav-dropdown-menu a:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.nav-cta {
  padding: 6px 16px;
  font-size: 14px;
  font-weight: 500;
  color: #fff;
  background: var(--text-primary);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: opacity 0.15s ease;
  text-decoration: none;
}

.nav-cta:hover {
  opacity: 0.85;
  text-decoration: none;
  color: #fff;
}

/* Mobile menu toggle */
.nav-mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--text-primary);
}

.nav-mobile-toggle svg {
  width: 20px;
  height: 20px;
}

/* --- Hero Section --- */
.hero {
  padding: 140px 0 80px;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-light);
}

.hero-content {
  max-width: 720px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  font-size: 13px;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: 100px;
  margin-bottom: 24px;
}

.hero-badge svg {
  width: 14px;
  height: 14px;
  color: var(--accent);
}

.hero h1 {
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.hero p {
  font-size: 18px;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 600px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all 0.15s ease;
  text-decoration: none;
  font-family: var(--font-sans);
  line-height: 1.4;
}

.btn-primary {
  color: #fff;
  background: var(--text-primary);
}

.btn-primary:hover {
  opacity: 0.85;
  text-decoration: none;
  color: #fff;
}

.btn-secondary {
  color: var(--text-primary);
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
}

.btn-secondary:hover {
  background: var(--bg-tertiary);
  text-decoration: none;
}

.btn-accent {
  color: #fff;
  background: var(--accent);
}

.btn-accent:hover {
  background: var(--accent-hover);
  text-decoration: none;
  color: #fff;
}

/* --- Section Common --- */
.section {
  padding: 80px 0;
}

.section-alt {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  margin-bottom: 48px;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(24px, 3.5vw, 32px);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.section-desc {
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-secondary);
  max-width: 640px;
}

/* --- About / Stats Section --- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.about-text h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.about-text p {
  font-size: 15px;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.stat-card {
  padding: 20px;
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  transition: box-shadow 0.15s ease;
}

.stat-card:hover {
  box-shadow: var(--shadow-md);
}

.stat-number {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
  margin-bottom: 4px;
}

.stat-label {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* --- Features Grid --- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  padding: 24px;
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
}

.feature-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--border-medium);
}

.feature-icon {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
  color: var(--text-primary);
}

.feature-icon svg {
  width: 20px;
  height: 20px;
}

.feature-card h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* --- Pillars Section --- */
.pillars-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.pillar-item {
  padding: 24px;
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  position: relative;
}

.pillar-number {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
  margin-bottom: 12px;
}

.pillar-item h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.pillar-item p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* --- Partners Section --- */
.partners-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.partner-card {
  padding: 32px;
  background: var(--bg-primary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  display: flex;
  gap: 24px;
  align-items: flex-start;
  transition: box-shadow 0.15s ease;
}

.partner-card:hover {
  box-shadow: var(--shadow-md);
}

.partner-logo {
  flex-shrink: 0;
  width: 80px;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.partner-logo img {
  max-width: 60px;
  max-height: 60px;
  object-fit: contain;
}

.partner-content h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.partner-content p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* --- CTA Section --- */
.cta-section {
  padding: 80px 0;
  text-align: center;
  border-top: 1px solid var(--border-light);
}

.cta-section h2 {
  font-size: clamp(24px, 3.5vw, 32px);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.cta-section p {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
}

.cta-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

/* --- Footer --- */
.footer {
  padding: 48px 0 32px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
  margin-top: 12px;
  max-width: 280px;
}

.footer-col h5 {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer-col ul {
  list-style: none;
}

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

.footer-col a {
  font-size: 14px;
  color: var(--text-secondary);
  text-decoration: none;
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-copyright {
  font-size: 13px;
  color: var(--text-tertiary);
}

.footer-qr {
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-qr img {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-light);
}

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

/* --- Callout Block (Notion-style) --- */
.callout {
  display: flex;
  gap: 12px;
  padding: 16px 20px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  margin: 24px 0;
}

.callout-icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
}

.callout p {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-secondary);
}

/* --- Divider --- */
.divider {
  height: 1px;
  background: var(--border-light);
  margin: 48px 0;
}

/* --- Mobile Responsive --- */
@media (max-width: 900px) {
  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    overflow-y: auto;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    padding: 12px;
    font-size: 16px;
    width: 100%;
  }

  .nav-dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    border: none;
    padding: 0 0 0 16px;
    display: none;
  }

  .nav-dropdown.open .nav-dropdown-menu {
    display: block;
  }

  .nav-cta {
    margin-top: 12px;
    width: 100%;
    text-align: center;
  }

  .nav-mobile-toggle {
    display: block;
  }

  .hero {
    padding: 120px 0 60px;
  }

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

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

  .pillars-list {
    grid-template-columns: 1fr 1fr;
  }

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

  .partner-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

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

@media (max-width: 600px) {
  .container {
    padding: 0 16px;
  }

  .section {
    padding: 56px 0;
  }

  .hero h1 {
    font-size: 28px;
  }

  .hero p {
    font-size: 16px;
  }

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

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

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

  .pillars-list {
    grid-template-columns: 1fr;
  }

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

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* --- Animations --- */
.fade-in {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

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