/* roulang page: index */
:root {
      --primary: #1A3C6D;
      --accent: #F15A24;
      --bg-light: #F7F9FC;
      --text-heading: #2C3E50;
      --text-body: #5D6D7E;
      --text-muted: #B0BEC5;
      --success: #27AE60;
      --white: #FFFFFF;
      --card-shadow: 0 4px 20px rgba(26, 60, 109, 0.08);
      --card-shadow-hover: 0 8px 30px rgba(26, 60, 109, 0.15);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-data: "DIN Alternate", "Roboto", sans-serif;
      --max-width: 1200px;
      --nav-height: 72px;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-sans);
      font-weight: 400;
      font-size: 16px;
      line-height: 28px;
      color: var(--text-body);
      background-color: var(--white);
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, input, textarea {
      font-family: var(--font-sans);
    }

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

    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--white);
      height: var(--nav-height);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      display: flex;
      align-items: center;
    }

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

    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 20px;
      color: var(--primary);
      letter-spacing: 1px;
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 18px;
      line-height: 1;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 28px;
    }

    .nav-link {
      font-size: 15px;
      color: var(--text-heading);
      font-weight: 500;
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: border-color 0.2s, color 0.2s;
    }
    .nav-link:hover {
      color: var(--accent);
      border-bottom-color: var(--accent);
    }

    .btn-nav {
      background: var(--accent);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      background: var(--accent);
      transition: background 0.2s;
      border: none;
      cursor: pointer;
    }
    .btn-nav:hover {
      background: #D94E1A;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 4px;
      background: transparent;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
      transition: 0.2s;
    }

    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        align-items: flex-start;
        padding: 24px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.08);
        gap: 16px;
      }
      .nav-menu.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .btn-nav.desktop {
        display: none;
      }
      .nav-menu .btn-nav {
        align-self: center;
        width: 100%;
        text-align: center;
      }
    }

    /* 通用板块 */
    .section {
      padding: 90px 0;
    }
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
    }

    .section-title {
      font-size: 30px;
      font-weight: 600;
      color: var(--text-heading);
      margin-bottom: 16px;
      line-height: 1.4;
    }
    .section-subtitle {
      color: var(--text-body);
      max-width: 600px;
      margin-bottom: 40px;
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      cursor: pointer;
      transition: background 0.2s, transform 0.1s;
      box-shadow: 0 4px 10px rgba(241,90,36,0.25);
    }
    .btn-primary:hover {
      background: #D94E1A;
      transform: translateY(-1px);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 13px 31px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      cursor: pointer;
      transition: background 0.2s, color 0.2s;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }

    /* Hero */
    .hero {
      background-color: var(--bg-light);
      display: flex;
      align-items: center;
      min-height: 85vh;
      padding: 40px 0;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      align-items: center;
      gap: 60px;
    }
    .hero h1 {
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
      line-height: 1.2;
      margin-bottom: 24px;
    }
    .hero-desc {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .data-cards {
      display: flex;
      flex-direction: column;
      gap: 20px;
    }
    .data-card {
      background: white;
      padding: 20px;
      border-radius: 16px;
      box-shadow: var(--card-shadow);
      display: flex;
      align-items: center;
      gap: 20px;
    }
    .data-number {
      font-family: var(--font-data);
      font-size: 36px;
      font-weight: 700;
      color: var(--accent);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .hero h1 {
        font-size: 32px;
      }
      .data-cards {
        flex-direction: row;
        flex-wrap: wrap;
      }
    }

    /* 数据看板 */
    .dashboard-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
    }
    .stat-card {
      background: var(--bg-light);
      padding: 28px 20px;
      border-radius: var(--radius-card);
      text-align: center;
      border-bottom: 4px solid var(--accent);
    }
    .stat-number {
      font-family: var(--font-data);
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      color: var(--text-body);
      margin-top: 10px;
    }
    @media (max-width: 768px) {
      .dashboard-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    /* 服务卡片 */
    .cards-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 30px;
    }
    .service-card {
      background: white;
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      transition: box-shadow 0.2s, border 0.2s;
      border-bottom: 3px solid transparent;
    }
    .service-card:hover {
      box-shadow: var(--card-shadow-hover);
      border-bottom-color: var(--primary);
    }
    .service-icon {
      color: var(--accent);
      font-size: 32px;
      margin-bottom: 16px;
    }
    .service-card h3 {
      font-size: 20px;
      color: var(--text-heading);
      margin-bottom: 10px;
    }
    @media (max-width: 1024px) {
      .cards-grid {
        grid-template-columns: repeat(2,1fr);
      }
    }
    @media (max-width: 600px) {
      .cards-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 结果对比 */
    .compare-row {
      display: flex;
      gap: 30px;
      flex-wrap: wrap;
    }
    .compare-box {
      flex: 1;
      background: var(--bg-light);
      border-radius: var(--radius-card);
      padding: 30px;
    }
    .compare-value {
      font-family: var(--font-data);
      font-size: 38px;
      color: var(--accent);
    }

    /* 流程 */
    .steps {
      display: flex;
      justify-content: space-between;
      text-align: center;
    }
    .step {
      flex: 1;
      position: relative;
    }
    .step-number {
      width: 40px;
      height: 40px;
      background: var(--primary);
      color: white;
      border-radius: 50%;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      .steps {
        flex-direction: column;
        gap: 24px;
      }
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--text-muted);
      padding: 16px 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      color: var(--text-heading);
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s;
      color: var(--text-body);
    }
    .faq-item.open .faq-answer {
      max-height: 150px;
    }

    /* 表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 50px;
    }
    .form input, .form textarea {
      width: 100%;
      padding: 14px;
      border: 1px solid var(--text-muted);
      border-radius: var(--radius-input);
      margin-bottom: 16px;
    }
    .form input:focus, .form textarea:focus {
      border-color: var(--primary);
      outline: none;
    }
    @media (max-width: 768px) {
      .contact-grid {
        grid-template-columns: 1fr;
      }
    }

    .footer {
      background: var(--primary);
      color: #cbd5e1;
      padding: 60px 0 30px;
    }
    .footer a {
      color: #cbd5e1;
    }
    .back-top {
      position: fixed;
      right: 24px;
      bottom: 24px;
      background: var(--accent);
      width: 44px;
      height: 44px;
      border-radius: 50%;
      color: white;
      border: none;
    }