/* roulang page: index */
:root {
      --primary: #FF6B1A;
      --primary-dark: #E55A0A;
      --secondary: #1A1A2E;
      --bg-light: #F5F6FA;
      --white: #FFFFFF;
      --text-dark: #1F2329;
      --text-muted: #86909C;
      --border-light: #E5E8EF;
      --success: #00B578;
      --warning: #FF9F0A;
      --error: #FA5151;
      --radius-lg: 12px;
      --radius-md: 8px;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --container-max: 1200px;
      --space-section: 80px;
      --space-mobile-section: 48px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

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

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
      body {
        font-size: 15px;
      }
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: all 0.2s ease;
      border: none;
      line-height: 1.2;
      text-align: center;
    }

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

    .btn-primary:hover {
      background-color: var(--primary-dark);
      box-shadow: 0 4px 16px rgba(255,107,26,0.3);
      transform: translateY(-1px);
    }

    .btn-primary:active {
      transform: scale(0.97);
    }

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

    .btn-secondary:hover {
      background-color: rgba(255,107,26,0.04);
    }

    .btn-light {
      background-color: var(--white);
      color: var(--primary);
    }
    .btn-light:hover {
      background-color: #f0f0f0;
    }

    .btn-outline-light {
      background: transparent;
      border: 1.5px solid var(--white);
      color: var(--white);
    }
    .btn-outline-light:hover {
      background-color: rgba(255,255,255,0.1);
    }

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: var(--white);
      box-shadow: 0 1px 0 var(--border-light);
      z-index: 100;
      display: flex;
      align-items: center;
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }

    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--secondary);
      display: flex;
      align-items: baseline;
    }
    .logo span {
      color: var(--primary);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }

    .nav-menu a {
      font-size: 15px;
      color: var(--text-dark);
      padding: 4px 0;
      border-bottom: 2px solid transparent;
      transition: color 0.2s, border-color 0.2s;
    }

    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }

    .header-cta {
      display: flex;
      align-items: center;
      gap: 16px;
    }

    .mobile-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--text-dark);
      cursor: pointer;
    }

    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 24px;
        box-shadow: 0 4px 12px rgba(0,0,0,0.05);
        gap: 20px;
      }
      .nav-menu.open {
        display: flex;
      }
      .mobile-toggle {
        display: block;
      }
      .header-cta .btn {
        display: none;
      }
    }

    /* 板块间距 */
    section {
      padding: var(--space-section) 0;
    }

    @media (max-width: 768px) {
      section {
        padding: var(--space-mobile-section) 0;
      }
    }

    /* Hero */
    .hero {
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
      padding-top: 120px;
      padding-bottom: 80px;
    }
    .hero::before {
      content: "";
      position: absolute;
      top: -100px;
      right: -100px;
      width: 500px;
      height: 500px;
      background: radial-gradient(circle, rgba(255,107,26,0.08) 0%, rgba(245,246,250,0) 70%);
      border-radius: 50%;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 40px;
    }

    .hero-content {
      flex: 1;
    }

    .hero-content h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--secondary);
      margin-bottom: 16px;
    }

    .hero-content .subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
    }

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

    .hero-image {
      flex: 1;
      position: relative;
    }

    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      width: 100%;
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero-content h1 {
        font-size: 28px;
      }
      .hero-content .subtitle {
        font-size: 16px;
      }
    }

    /* 区块标题 */
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 28px;
      font-weight: 700;
      color: var(--secondary);
      margin-bottom: 12px;
    }

    /* 核心优势 2+1 错位 */
    .features-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
      max-width: 900px;
      margin: 0 auto;
    }
    .feature-card {
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: all 0.2s ease;
    }
    .feature-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }
    .feature-card i {
      font-size: 28px;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .feature-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .feature-card p {
      color: var(--text-muted);
    }
    .feature-card.large {
      grid-column: span 2;
      max-width: 66%;
      margin: 0 auto;
    }

    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
      .feature-card.large {
        grid-column: span 1;
        max-width: 100%;
      }
    }

    /* 解决方案交替 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 64px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-text {
      flex: 1;
    }
    .solution-text h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
      color: var(--secondary);
    }
    .solution-text ul {
      list-style: none;
      margin-top: 16px;
    }
    .solution-text li {
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .solution-text li i {
      color: var(--success);
    }
    .solution-img {
      flex: 1;
    }
    .solution-img img {
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      width: 100%;
    }
    @media (max-width: 768px) {
      .solution-row, .solution-row.reverse {
        flex-direction: column;
      }
    }

    /* 数据证言深色区 */
    .dark-bg {
      background-color: var(--secondary);
      color: white;
    }
    .stats-grid {
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
      gap: 32px;
    }
    .stat-item .number {
      font-size: 42px;
      font-weight: 700;
      color: var(--primary);
    }
    .testimonial-card {
      background: rgba(255,255,255,0.06);
      border-radius: var(--radius-lg);
      padding: 20px;
      margin-top: 32px;
      max-width: 600px;
      margin-left: auto;
      margin-right: auto;
      color: #ddd;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 16px 0;
    }
    .faq-question {
      font-size: 18px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-dark);
      margin-top: 8px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
    }

    /* CTA */
    .cta-section {
      background: linear-gradient(135deg, #FF6B1A 0%, #E55A0A 100%);
      text-align: center;
    }
    .cta-section h2 {
      color: white;
      font-size: 28px;
    }
    .cta-buttons {
      display: flex;
      gap: 16px;
      justify-content: center;
      margin-top: 24px;
    }

    /* 页脚 */
    .site-footer {
      background: var(--secondary);
      color: var(--text-muted);
      padding: 32px 0;
    }
    .footer-content {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
    }
    @media (max-width: 768px) {
      .footer-content {
        flex-direction: column;
        text-align: center;
      }
      .cta-buttons {
        flex-direction: column;
        align-items: center;
      }
    }