/* roulang page: index */
:root {
      --primary: #1A5FDC;
      --primary-deep: #0F3D9E;
      --accent: #2E8B57;
      --bg-light: #F7F8FA;
      --card-bg: #FFFFFF;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --white: #ffffff;
      --footer-bg: #1E293B;
      --gray-light: #CBD5E1;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
      --transition: 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    .section-padding {
      padding: 80px 0;
    }
    h2 {
      font-size: 28px;
      font-weight: 600;
      letter-spacing: -0.2px;
      margin-bottom: 16px;
      color: var(--text-main);
    }
    .text-muted {
      color: var(--text-muted);
    }
    .btn {
      display: inline-block;
      font-weight: 600;
      font-size: 16px;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: var(--transition);
      text-align: center;
      cursor: pointer;
      border: none;
      background: transparent;
    }
    .btn-primary {
      background-color: var(--primary);
      color: white;
      border: 2px solid var(--primary);
    }
    .btn-primary:hover {
      background-color: var(--primary-deep);
      border-color: var(--primary-deep);
      box-shadow: var(--shadow-sm);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 2px solid var(--primary);
    }
    .btn-outline:hover {
      background-color: rgba(26, 95, 220, 0.08);
    }
    .btn-white {
      background: white;
      color: var(--primary);
      border: 2px solid white;
    }
    .btn-white:hover {
      background: #f0f4ff;
      border-color: #f0f4ff;
    }

    /* header */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: white;
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      height: 64px;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
      font-size: 20px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      font-weight: 500;
    }
    .nav-links a {
      color: var(--text-main);
      font-size: 16px;
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--text-main);
      cursor: pointer;
    }

    /* hero */
    .hero {
      background: linear-gradient(180deg, #F7F8FA 0%, #FFFFFF 100%);
      display: flex;
      align-items: center;
      min-height: 500px;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
      flex-wrap: wrap;
    }
    .hero-left {
      flex: 1 1 400px;
    }
    .hero-right {
      flex: 1 1 400px;
    }
    .hero-right img {
      border-radius: 16px;
      box-shadow: var(--shadow-sm);
      width: 100%;
    }
    h1 {
      font-size: 36px;
      font-weight: 700;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
      color: var(--text-main);
      line-height: 1.3;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 12px;
    }
    .hero-desc {
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 500px;
    }
    .cta-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    /* 卡片系统 */
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: transform 0.25s ease, box-shadow 0.25s ease;
      height: 100%;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .card-icon {
      width: 56px;
      height: 56px;
      background: rgba(26, 95, 220, 0.1);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 28px;
    }
    h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
      color: var(--text-main);
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2x2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .service-card img {
      border-radius: 8px;
      margin-bottom: 16px;
      width: 100%;
      height: auto;
    }
    .link-arrow {
      font-weight: 600;
      color: var(--primary);
      display: inline-block;
      margin-top: 12px;
    }
    .link-arrow:hover {
      color: var(--primary-deep);
    }

    /* 数据区 */
    .data-section {
      background: rgba(26, 95, 220, 0.04);
      border-radius: 20px;
    }
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .data-number {
      font-size: 40px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.2;
    }
    .data-label {
      color: var(--text-muted);
      font-size: 14px;
      font-weight: 500;
    }

    /* 品牌墙 */
    .brand-grid {
      display: grid;
      grid-template-columns: repeat(6, 1fr);
      gap: 20px;
    }
    .brand-item {
      background: #f1f5f9;
      height: 80px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 10px;
      color: #94a3b8;
      font-weight: 600;
      transition: 0.2s;
      font-size: 14px;
    }
    .brand-item:hover {
      background: #dbeafe;
      color: var(--primary);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: white;
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: white;
      border: none;
      padding: 18px 16px;
      font-size: 18px;
      font-weight: 600;
      text-align: left;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-main);
      transition: 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s;
      background: #F7F8FA;
      padding: 0 16px;
    }
    .faq-answer.open {
      max-height: 200px;
      padding: 16px;
    }
    .arrow-icon {
      font-size: 14px;
      color: var(--text-muted);
    }

    /* CTA */
    .cta-banner {
      background: var(--primary);
      border-radius: 16px;
      text-align: center;
      padding: 60px 24px;
      color: white;
    }
    .cta-banner h2 {
      color: white;
    }
    .cta-banner .btn {
      margin-top: 24px;
    }

    /* footer */
    .site-footer {
      background: var(--footer-bg);
      color: var(--gray-light);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer-logo {
      font-size: 20px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    .footer-links a {
      display: block;
      color: var(--gray-light);
      margin-bottom: 10px;
      transition: color 0.2s;
    }
    .footer-links a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #334155;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .data-grid { grid-template-columns: repeat(2,1fr); }
      .brand-grid { grid-template-columns: repeat(4,1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .menu-toggle { display: block; }
      .mobile-menu {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: 16px;
        box-shadow: 0 4px 10px rgba(0,0,0,0.05);
        gap: 12px;
      }
      .mobile-menu.open { display: flex; }
      .hero-grid { flex-direction: column; }
      h1 { font-size: 28px; }
      h2 { font-size: 22px; }
      .grid-3, .grid-2x2, .data-grid { grid-template-columns: 1fr; }
      .brand-grid { grid-template-columns: repeat(3,1fr); }
      .footer-grid { grid-template-columns: 1fr; }
      .section-padding { padding: 60px 0; }
    }
    @media (max-width: 520px) {
      .container { padding: 0 16px; }
      .brand-grid { grid-template-columns: repeat(2,1fr); }
    }