/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CE5;
      --primary-active: #2E4BD0;
      --green: #00B578;
      --orange: #FF9F0A;
      --red: #FA5151;
      --bg: #F5F6FA;
      --card-bg: #FFFFFF;
      --section-bg: #F0F1F5;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --text-weak: #B0B6BE;
      --border: #E0E3E8;
      --radius-lg: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 2px 8px rgba(31, 35, 41, 0.04);
      --shadow-hover: 0 4px 16px rgba(31, 35, 41, 0.08);
      --shadow-focus: 0 0 0 4px rgba(78, 110, 242, 0.2);
      --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --container-max: 1200px;
      --spacing-xs: 8px;
      --spacing-sm: 16px;
      --spacing-md: 24px;
      --spacing-lg: 48px;
      --spacing-xl: 80px;
      --nav-height: 64px;
    }

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

    body {
      font-family: var(--font-system);
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    a {
      color: var(--primary);
      text-decoration: none;
      transition: text-decoration 0.2s;
    }

    a:hover {
      text-decoration: underline;
    }

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      font-size: 16px;
      font-weight: 600;
      border-radius: var(--radius-lg);
      padding: 0 24px;
      height: 48px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background-color 0.2s, box-shadow 0.2s, transform 0.1s, border-color 0.2s;
      text-decoration: none;
      line-height: 1.2;
    }

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

    .btn-primary:hover {
      background-color: var(--primary-hover);
      box-shadow: var(--shadow-focus);
    }

    .btn-primary:active {
      background-color: var(--primary-active);
      transform: scale(0.98);
    }

    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
    }

    .btn-secondary:hover {
      background-color: rgba(78, 110, 242, 0.06);
    }

    input, textarea {
      font-family: inherit;
      font-size: 16px;
      border: 1px solid var(--border);
      border-radius: var(--radius-lg);
      padding: 0 16px;
      height: 48px;
      width: 100%;
      background: #fff;
      transition: border-color 0.2s, box-shadow 0.2s;
      outline: none;
    }

    input:focus, textarea:focus {
      border-color: var(--primary);
      box-shadow: 0 0 0 4px rgba(78, 110, 242, 0.15);
    }

    h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text-primary);
    }

    h2 {
      font-size: 28px;
      font-weight: 600;
      line-height: 1.4;
      color: var(--text-primary);
    }

    h3 {
      font-size: 20px;
      font-weight: 500;
      line-height: 1.5;
      color: var(--text-primary);
    }

    .section {
      padding: var(--spacing-xl) 0;
    }

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: #fff;
      height: var(--nav-height);
      z-index: 100;
      box-shadow: 0 1px 0 rgba(0,0,0,0.04);
      transition: box-shadow 0.3s;
    }

    .nav.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    }

    .nav .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-primary);
      text-decoration: none;
      letter-spacing: 0.5px;
    }

    .logo span {
      color: var(--primary);
    }

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

    .nav-links a {
      color: var(--text-secondary);
      font-weight: 500;
      font-size: 15px;
      text-decoration: none;
      transition: color 0.2s;
    }

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 8px;
    }

    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      border-radius: 2px;
      transition: 0.2s;
    }

    /* Hero */
    .hero {
      background: #fff;
      padding: calc(var(--nav-height) + 60px) 0 80px;
    }

    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }

    .hero-content h1 {
      margin-bottom: 20px;
    }

    .hero-content p {
      color: var(--text-secondary);
      margin-bottom: 32px;
      font-size: 16px;
      line-height: 1.7;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .hero-image {
      background: #f0f3ff;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: inset 0 0 0 1px rgba(0,0,0,0.02);
      aspect-ratio: 4/3;
    }

    .hero-image img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }

    /* 数据看板 */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: 40px;
    }

    .metric-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      text-align: center;
      box-shadow: var(--shadow-card);
      transition: box-shadow 0.2s;
    }

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

    .metric-number {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--primary);
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
    }

    .metric-number.green {
      color: var(--green);
    }

    .metric-label {
      color: var(--text-secondary);
      font-size: 14px;
      margin-top: 8px;
    }

    /* 服务 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 40px;
    }

    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: box-shadow 0.2s;
      display: flex;
      flex-direction: column;
    }

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

    .service-icon {
      width: 56px;
      height: 56px;
      border-radius: var(--radius-sm);
      background: rgba(78, 110, 242, 0.08);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 24px;
      color: var(--primary);
      font-size: 28px;
    }

    .service-icon.green {
      background: rgba(0, 181, 120, 0.08);
      color: var(--green);
    }

    .service-card h3 {
      margin-bottom: 12px;
    }

    .service-card p {
      color: var(--text-secondary);
      margin-bottom: 20px;
      flex: 1;
    }

    .service-link {
      font-weight: 500;
      font-size: 15px;
    }

    /* 对比 */
    .compare-wrapper {
      background: var(--section-bg);
    }

    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
      margin-top: 40px;
    }

    .compare-card {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      padding: 32px;
      box-shadow: var(--shadow-card);
    }

    .compare-card.traditional {
      border: 1px solid var(--border);
      box-shadow: none;
      background: #FAFBFC;
    }

    .compare-card.tanqiuba {
      border-left: 4px solid var(--primary);
      background: #fff;
    }

    .compare-card h3 {
      margin-bottom: 24px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .compare-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 12px 0;
      border-bottom: 1px solid #f0f0f0;
    }

    .compare-row:last-child {
      border-bottom: none;
    }

    .compare-label {
      color: var(--text-secondary);
    }

    .compare-value {
      font-weight: 500;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .check-icon {
      color: var(--green);
      font-weight: 600;
    }

    .compare-cta {
      margin-top: 40px;
      text-align: center;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 40px auto 0;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .faq-item {
      background: var(--card-bg);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }

    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 20px 24px;
      font-size: 16px;
      font-weight: 500;
      color: var(--text-primary);
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      text-align: left;
      font-family: inherit;
    }

    .faq-icon {
      font-size: 20px;
      color: var(--primary);
      font-weight: 400;
      transition: transform 0.2s;
    }

    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-secondary);
      display: none;
      line-height: 1.6;
    }

    .faq-item.open .faq-answer {
      display: block;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* 表单 */
    .contact-card {
      max-width: 600px;
      margin: 40px auto 0;
      background: #fff;
      border-radius: var(--radius-lg);
      padding: 40px;
      box-shadow: var(--shadow-card);
    }

    .form-group {
      margin-bottom: 20px;
    }

    .form-group label {
      display: block;
      margin-bottom: 8px;
      font-weight: 500;
      font-size: 14px;
    }

    .form-submit {
      width: 100%;
      margin-top: 8px;
    }

    .form-note {
      text-align: center;
      margin-top: 16px;
      font-size: 14px;
      color: var(--text-weak);
    }

    /* 页脚 */
    .footer {
      background: #fff;
      border-top: 1px solid var(--border);
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }

    .footer-brand p {
      color: var(--text-secondary);
      margin-top: 16px;
      font-size: 14px;
    }

    .footer-links h4 {
      font-weight: 600;
      margin-bottom: 16px;
      font-size: 15px;
    }

    .footer-links a {
      display: block;
      color: var(--text-secondary);
      font-size: 14px;
      margin-bottom: 10px;
      text-decoration: none;
    }

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

    .footer-contact p {
      color: var(--text-secondary);
      font-size: 14px;
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .copyright {
      margin-top: 40px;
      padding-top: 20px;
      border-top: 1px solid #eee;
      text-align: center;
      color: var(--text-weak);
      font-size: 14px;
    }

    /* 移动端悬浮按钮 */
    .mobile-cta {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: #fff;
      padding: 12px 16px;
      box-shadow: 0 -2px 10px rgba(0,0,0,0.06);
      z-index: 99;
    }

    .mobile-cta .btn-primary {
      width: 100%;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .services-grid {
        grid-template-columns: 1fr 1fr;
      }
      .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 768px) {
      h1 { font-size: 28px; }
      h2 { font-size: 22px; }
      h3 { font-size: 18px; }
      .section { padding: 60px 0; }
      .container { padding: 0 16px; }
      .hero { padding-top: calc(var(--nav-height) + 40px); }

      .nav-links {
        display: none;
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: #fff;
        flex-direction: column;
        padding: 24px;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        gap: 20px;
      }

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

      .hamburger {
        display: flex;
      }

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

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

      .metrics-grid {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
      }
      .metric-number { font-size: 36px; }

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

      .mobile-cta {
        display: block;
      }
    }