/* roulang page: index */
:root {
      --primary: #2D4A3E;
      --primary-deep: #1E332B;
      --accent: #E85D04;
      --accent-hover: #C94D00;
      --bg-light: #FAF7F2;
      --bg-subtle: #EEF0EB;
      --text-dark: #1E1C1A;
      --text-body: #4A4845;
      --text-muted: #8C8985;
      --text-on-dark: #F5F2EB;
      --white: #FFFFFF;
      --border-light: #E8E5DF;
      --shadow-sm: 0 2px 12px rgba(45,74,62,0.08);
      --shadow-md: 0 8px 24px rgba(45,74,62,0.15);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: all 0.25s ease;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --max-width: 1200px;
      --section-space: 100px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    h1, h2, h3, h4 {
      color: var(--text-dark);
      font-weight: 600;
    }

    h1 {
      font-size: 48px;
      font-weight: 700;
      letter-spacing: -0.5px;
      line-height: 1.2;
    }

    h2 {
      font-size: 36px;
      font-weight: 600;
      margin-bottom: 1.2rem;
    }

    h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 0.6rem;
    }

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

    a:hover {
      text-decoration: underline;
    }

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

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      transition: var(--transition);
      border: none;
      cursor: pointer;
      font-size: 16px;
      gap: 8px;
    }

    .btn-primary {
      background: var(--accent);
      color: var(--white);
      box-shadow: 0 2px 8px rgba(232,93,4,0.2);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      box-shadow: 0 4px 14px rgba(232,93,4,0.3);
      transform: translateY(-1px);
      color: white;
      text-decoration: none;
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
      text-decoration: none;
    }

    .btn-light {
      border: 2px solid var(--text-on-dark);
      color: var(--text-on-dark);
      background: transparent;
    }
    .btn-light:hover {
      background: var(--text-on-dark);
      color: var(--primary-deep);
    }

    .btn-text {
      background: transparent;
      border: none;
      color: var(--accent);
      padding: 8px 0;
      font-weight: 600;
      text-decoration: underline;
    }
    .btn-text:hover {
      text-decoration: none;
      color: var(--accent-hover);
    }

    /* header / nav */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.02);
      transition: background 0.3s, backdrop-filter 0.3s;
    }
    .site-header.scrolled {
      background: rgba(29,40,32,0.95);
      backdrop-filter: blur(16px);
    }
    .site-header.scrolled .logo-text,
    .site-header.scrolled .nav-link {
      color: var(--text-on-dark);
    }
    .site-header.scrolled .logo-icon {
      color: var(--accent);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      height: 72px;
    }
    .logo-area {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
    }
    .logo-icon {
      font-size: 28px;
      color: var(--primary);
      transition: color 0.3s;
    }
    .logo-text {
      color: var(--primary);
      transition: color 0.3s;
      letter-spacing: -0.3px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }
    .nav-link {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-body);
      transition: color 0.2s;
      padding: 4px 0;
      border-bottom: 2px solid transparent;
    }
    .nav-link:hover {
      color: var(--accent);
      text-decoration: none;
    }
    .active-link {
      color: var(--accent);
      border-bottom-color: var(--accent);
    }
    .header-actions {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .search-toggle {
      background: none;
      border: none;
      font-size: 18px;
      color: var(--text-body);
      cursor: pointer;
      transition: color 0.2s;
    }
    .site-header.scrolled .search-toggle {
      color: var(--text-on-dark);
    }
    .login-link {
      font-weight: 500;
      color: var(--text-body);
    }
    .site-header.scrolled .login-link {
      color: var(--text-on-dark);
    }
    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--primary);
    }
    .site-header.scrolled .mobile-menu-btn {
      color: white;
    }

    /* sections */
    section {
      padding: var(--section-space) 0;
    }

    .bg-subtle {
      background-color: var(--bg-subtle);
    }

    .bg-dark {
      background-color: var(--primary-deep);
      color: var(--text-on-dark);
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-left {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .hero-badge-group {
      display: flex;
      gap: 32px;
      margin: 8px 0 16px;
    }
    .hero-badge .number {
      font-size: 38px;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.2;
    }
    .hero-badge .label {
      font-size: 14px;
      color: var(--text-muted);
    }
    .hero-image img {
      border-radius: 16px;
      box-shadow: var(--shadow-md);
      width: 100%;
    }

    .feature-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 64px;
    }
    .feature-img img {
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
    }
    .feature-text ul {
      list-style: none;
      padding-left: 0;
      margin: 16px 0;
    }
    .feature-text ul li {
      padding-left: 24px;
      position: relative;
      margin-bottom: 10px;
    }
    .feature-text ul li::before {
      content: "●";
      color: var(--accent);
      position: absolute;
      left: 0;
      font-size: 14px;
    }

    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
      margin-top: 40px;
    }
    .scenario-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      border: 1px solid var(--border-light);
      transition: var(--transition);
      box-shadow: var(--shadow-sm);
    }
    .scenario-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .scenario-img {
      height: 200px;
      overflow: hidden;
      position: relative;
    }
    .scenario-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: 0.3s;
    }
    .scenario-card:hover .scenario-img img {
      filter: brightness(0.7);
    }
    .scenario-content {
      padding: 20px;
    }

    .cases-grid {
      display: grid;
      grid-template-columns: 1fr 2fr;
      gap: 48px;
      align-items: center;
    }
    .big-number {
      font-size: 64px;
      font-weight: 800;
      color: var(--accent);
      line-height: 1;
    }
    .case-cards {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
    }
    .case-card {
      background: var(--white);
      padding: 20px;
      border-radius: var(--radius-card);
      border-left: 4px solid var(--primary);
      box-shadow: var(--shadow-sm);
    }
    .tag {
      background: var(--primary);
      color: white;
      padding: 2px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 12px;
    }

    .accordion-item {
      background: var(--white);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      overflow: hidden;
    }
    .accordion-title {
      padding: 18px 24px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: var(--white);
    }
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0 24px;
      background: #fafaf8;
    }
    .accordion-item.active .accordion-content {
      max-height: 200px;
      padding: 16px 24px;
    }
    .accordion-item.active .accordion-title {
      color: var(--accent);
    }

    .cta-banner {
      text-align: center;
      padding: 80px 24px;
    }
    .cta-buttons {
      display: flex;
      justify-content: center;
      gap: 24px;
      margin-top: 32px;
      flex-wrap: wrap;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1.5fr;
      gap: 40px;
      padding: 60px 0 40px;
      color: #cbd5d1;
    }
    .footer-links a {
      display: block;
      color: #a3b5ad;
      margin-bottom: 8px;
    }
    .copyright {
      border-top: 1px solid rgba(245,242,235,0.15);
      padding: 20px 0;
      font-size: 13px;
      color: #8a9b94;
    }

    @media (max-width: 1024px) {
      h1 { font-size: 40px; }
      h2 { font-size: 30px; }
      .hero-grid, .feature-row, .cases-grid {
        grid-template-columns: 1fr;
      }
      .feature-row.reverse {
        display: flex;
        flex-direction: column-reverse;
      }
      .case-cards {
        grid-template-columns: 1fr;
      }
    }

    @media (max-width: 768px) {
      .nav-links, .header-actions .login-link, .header-actions .btn {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .scenario-grid {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      h1 { font-size: 34px; }
      section { padding: 70px 0; }
    }