/* roulang page: index */
:root {
      --primary: #1A5FDC;
      --primary-dark: #1349b0;
      --accent: #F97316;
      --accent-dark: #EA580C;
      --bg: #FFFFFF;
      --bg-alt: #F8FAFC;
      --text-main: #0F172A;
      --text-secondary: #475569;
      --text-muted: #94A3B8;
      --border: #E2E8F0;
      --success: #10B981;
      --danger: #EF4444;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-md: 0 10px 25px rgba(0,0,0,0.08), 0 4px 10px rgba(0,0,0,0.04);
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      --font-number: "Inter", "SF Pro Display", system-ui;
      --transition: 0.25s ease;
      --container: 1280px;
      --nav-height: 64px;
    }
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-sans);
      background: var(--bg);
      color: var(--text-main);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      padding-top: var(--nav-height);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: var(--bg);
      border-bottom: 1px solid var(--border);
      z-index: 1000;
      transition: box-shadow var(--transition);
      display: flex;
      align-items: center;
    }
    .header.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.25rem;
      color: var(--primary);
    }
    .logo img {
      width: 36px;
      height: 36px;
      border-radius: 8px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-secondary);
      transition: color var(--transition);
      font-size: 0.95rem;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 0.95rem;
      transition: all var(--transition);
      cursor: pointer;
      border: none;
      background: transparent;
      white-space: nowrap;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      box-shadow: 0 2px 6px rgba(249,115,22,0.25);
    }
    .btn-primary:hover {
      background: var(--accent-dark);
      transform: translateY(-1px);
    }
    .btn-outline {
      border: 1px solid var(--primary);
      color: var(--primary);
      background: var(--bg);
    }
    .btn-outline:hover {
      background: rgba(26,95,220,0.05);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-main);
      transition: var(--transition);
      display: block;
    }
    /* Hero */
    .hero {
      padding: 60px 0;
      background: var(--bg);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 2.75rem;
      font-weight: 700;
      line-height: 1.25;
      color: var(--text-main);
      margin-bottom: 1rem;
    }
    .hero-content h1 span {
      color: var(--accent);
    }
    .hero-sub {
      font-size: 1.1rem;
      color: var(--text-secondary);
      margin-bottom: 2rem;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 2rem;
    }
    .trust-signal {
      display: flex;
      align-items: center;
      gap: 12px;
      color: var(--text-muted);
      font-size: 0.9rem;
    }
    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-md);
      width: 100%;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    /* 指标看板 */
    .metrics {
      background: var(--bg-alt);
      padding: 60px 0;
    }
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .metric-number {
      font-family: var(--font-number);
      font-size: 3rem;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.1;
    }
    .metric-label {
      color: var(--text-secondary);
      font-size: 1rem;
      margin-top: 8px;
    }
    /* 服务矩阵 */
    .services {
      padding: 80px 0;
      background: var(--bg);
    }
    .section-title {
      font-size: 2rem;
      font-weight: 600;
      margin-bottom: 1rem;
      color: var(--text-main);
    }
    .section-sub {
      color: var(--text-secondary);
      margin-bottom: 2.5rem;
      max-width: 600px;
    }
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--bg);
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 24px;
      transition: all var(--transition);
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
    }
    .service-card.featured {
      background: #F0F4FF;
      border-color: #cbd5e1;
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .service-icon {
      width: 48px;
      height: 48px;
      background: rgba(26,95,220,0.1);
      border-radius: var(--radius-sm);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 16px;
      color: var(--primary);
      font-size: 1.5rem;
    }
    .service-card h3 {
      font-size: 1.25rem;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .service-card p {
      color: var(--text-secondary);
      font-size: 0.95rem;
      flex: 1;
    }
    .service-link {
      color: var(--primary);
      font-weight: 600;
      margin-top: 12px;
      font-size: 0.9rem;
    }
    /* 对比区 */
    .compare {
      padding: 80px 0;
      background: var(--bg-alt);
    }
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      gap: 32px;
      align-items: start;
    }
    .compare-col {
      background: var(--bg);
      border-radius: var(--radius);
      padding: 32px;
      border: 1px solid var(--border);
    }
    .compare-col.before {
      background: #F1F5F9;
    }
    .compare-col h3 {
      font-size: 1.4rem;
      margin-bottom: 16px;
    }
    .compare-list {
      list-style: none;
    }
    .compare-list li {
      margin-bottom: 12px;
      display: flex;
      align-items: center;
      gap: 8px;
      color: var(--text-secondary);
    }
    .compare-divider {
      font-size: 2rem;
      font-weight: 700;
      color: var(--primary);
      align-self: center;
    }
    .compare-conclusion {
      margin-top: 2rem;
      font-weight: 600;
      font-size: 1.2rem;
      color: var(--primary);
      text-align: center;
    }
    /* FAQ */
    .faq {
      padding: 80px 0;
      background: var(--bg);
    }
    .faq-grid {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 16px 0;
      font-weight: 600;
      font-size: 1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-main);
      text-align: left;
    }
    .faq-icon {
      transition: transform 0.3s ease;
      font-size: 1.3rem;
      color: var(--primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      color: var(--text-secondary);
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 16px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    /* 表单 */
    .contact {
      padding: 80px 0;
      background: var(--bg-alt);
    }
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .contact-form {
      background: var(--bg);
      padding: 32px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border);
    }
    .form-group {
      margin-bottom: 16px;
    }
    .form-group input {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border);
      border-radius: var(--radius-sm);
      font-size: 1rem;
      transition: 0.2s;
      background: var(--bg);
    }
    .form-group input:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(26,95,220,0.15);
    }
    .btn-submit {
      width: 100%;
      background: var(--accent);
      color: white;
      border: none;
      padding: 12px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 1rem;
      cursor: pointer;
      transition: var(--transition);
    }
    .btn-submit:hover {
      background: var(--accent-dark);
    }
    .privacy-note {
      font-size: 0.8rem;
      color: var(--text-muted);
      margin-top: 8px;
      text-align: center;
    }
    /* 页脚 */
    .footer {
      background: #0F172A;
      color: #cbd5e1;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer h4 {
      color: white;
      margin-bottom: 12px;
      font-size: 1rem;
    }
    .footer a {
      color: #94A3B8;
      font-size: 0.9rem;
      display: block;
      margin-bottom: 6px;
    }
    .footer a:hover {
      color: white;
    }
    .copyright {
      border-top: 1px solid #334155;
      margin-top: 32px;
      padding-top: 16px;
      text-align: center;
      font-size: 0.85rem;
      color: #64748b;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid, .contact-grid {
        grid-template-columns: 1fr;
      }
      .hero-image {
        order: -1;
      }
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: var(--bg);
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow-md);
        gap: 16px;
      }
      .nav-links.open {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .services-grid {
        grid-template-columns: 1fr;
      }
      .compare-grid {
        grid-template-columns: 1fr;
      }
      .compare-divider {
        display: none;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-content h1 {
        font-size: 2rem;
      }
    }