/* roulang page: index */
/* ----- 设计变量与全局重置 ----- */
    :root {
      --primary-blue: #4E6EF2;
      --primary-blue-hover: #3A5AD9;
      --functional-green: #00B578;
      --warning-orange: #FF9F0A;
      --error-red: #FA5151;
      --bg-light: #F5F6FA;
      --surface-white: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --radius-card: 12px;
      --radius-button: 12px;
      --shadow-card: 0 4px 12px rgba(0, 0, 0, 0.03);
      --shadow-nav: 0 1px 0 rgba(0,0,0,0.04);
      --transition-base: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-light);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition-base);
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* ----- 导航 (白底平台导航) ----- */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--surface-white);
      box-shadow: 0 1px 0 rgba(0,0,0,0.04);
      backdrop-filter: blur(8px);
      background: rgba(255,255,255,0.92);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 64px;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--primary-blue);
    }

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

    .nav-link {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-primary);
      position: relative;
      padding: 4px 0;
      transition: color var(--transition-base);
    }

    .nav-link:hover,
    .nav-link.active {
      color: var(--primary-blue);
    }

    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -20px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary-blue);
    }

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

    /* ----- 首屏 Hero (数据看板风格) ----- */
    .hero-section {
      padding: 80px 0 64px;
      background: var(--surface-white);
      border-radius: 0 0 32px 32px;
      margin-bottom: 40px;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
      flex-wrap: wrap;
    }

    .hero-content {
      flex: 1 1 400px;
    }

    .hero-badge {
      display: inline-block;
      background: #EEF1FE;
      color: var(--primary-blue);
      font-weight: 600;
      font-size: 14px;
      padding: 4px 12px;
      border-radius: 20px;
      margin-bottom: 20px;
    }

    h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 16px;
      color: var(--text-primary);
    }

    .hero-subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      line-height: 1.65;
      margin-bottom: 28px;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 12px 28px;
      border-radius: var(--radius-button);
      font-weight: 600;
      font-size: 16px;
      transition: all var(--transition-base);
      border: none;
      cursor: pointer;
      text-align: center;
    }

    .btn-primary {
      background: var(--primary-blue);
      color: white;
      box-shadow: 0 4px 10px rgba(78,110,242,0.25);
    }

    .btn-primary:hover {
      background: var(--primary-blue-hover);
      transform: scale(1.02);
      box-shadow: 0 6px 14px rgba(78,110,242,0.3);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--border-light);
      color: var(--text-primary);
    }

    .btn-outline:hover {
      background: #F5F6FA;
      border-color: var(--primary-blue);
      color: var(--primary-blue);
    }

    .hero-visual {
      flex: 1 1 450px;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }

    .metric-card {
      background: var(--surface-white);
      border-radius: var(--radius-card);
      padding: 20px;
      box-shadow: var(--shadow-card);
      border: 1px solid rgba(0,0,0,0.02);
    }

    .metric-label {
      font-size: 14px;
      color: var(--text-secondary);
      margin-bottom: 6px;
    }

    .metric-value {
      font-size: 32px;
      font-weight: 800;
      color: var(--text-primary);
    }

    .metric-trend {
      font-size: 14px;
      font-weight: 600;
      margin-top: 8px;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .trend-up { color: var(--functional-green); }
    .trend-down { color: var(--error-red); }

    .bg-placeholder {
      background: #F0F2F5;
      border-radius: var(--radius-card);
      width: 100%;
      height: 140px;
      object-fit: cover;
    }

    /* ----- 通用板块标题 ----- */
    .section {
      padding: 64px 0;
    }

    .section-header {
      text-align: center;
      margin-bottom: 48px;
    }

    h2 {
      font-size: 32px;
      font-weight: 700;
      margin-bottom: 12px;
      color: var(--text-primary);
    }

    .section-desc {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 640px;
      margin: 0 auto;
      line-height: 1.6;
    }

    /* ----- 服务卡片网格 ----- */
    .service-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .service-card {
      background: var(--surface-white);
      border-radius: var(--radius-card);
      padding: 28px 24px;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition-base), box-shadow var(--transition-base);
    }

    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: 0 12px 24px rgba(0,0,0,0.06);
    }

    .icon-badge {
      width: 48px;
      height: 48px;
      background: #EEF1FE;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary-blue);
    }

    .service-card h3 {
      font-size: 22px;
      font-weight: 700;
      margin-bottom: 8px;
    }

    .service-desc {
      color: var(--text-secondary);
      margin-bottom: 16px;
      line-height: 1.6;
    }

    .feature-list {
      list-style: none;
      margin-bottom: 20px;
    }

    .feature-list li {
      font-size: 14px;
      color: var(--text-primary);
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .feature-list li::before {
      content: "•";
      color: var(--primary-blue);
      font-weight: bold;
    }

    .micro-data {
      font-size: 14px;
      font-weight: 600;
      color: var(--functional-green);
      background: #F0FFF7;
      padding: 4px 10px;
      border-radius: 20px;
      display: inline-block;
    }

    /* ----- 对比表格 (去线化) ----- */
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }

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

    .compare-card.old {
      background: #FAFAFC;
    }

    .compare-title {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 24px;
    }

    .compare-row {
      display: flex;
      justify-content: space-between;
      padding: 12px 0;
      border-bottom: 1px solid #F0F2F5;
      font-size: 15px;
    }

    .arrow-up { color: var(--functional-green); font-weight: 600; }
    .arrow-down { color: var(--error-red); font-weight: 600; }

    /* ----- FAQ 手风琴 ----- */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    .faq-item {
      background: var(--surface-white);
      border-radius: var(--radius-card);
      padding: 20px 24px;
      box-shadow: var(--shadow-card);
      cursor: pointer;
      transition: background var(--transition-base);
    }

    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
    }

    .faq-icon {
      font-size: 24px;
      transition: transform 200ms ease;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      line-height: 1.6;
      margin-top: 0;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 16px;
    }

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

    /* ----- CTA 底部 ----- */
    .cta-section {
      background: #EEF1FE;
      border-radius: 24px;
      padding: 56px 32px;
      text-align: center;
      margin: 40px 0 64px;
    }

    .cta-text {
      font-size: 28px;
      font-weight: 700;
      margin-bottom: 16px;
    }

    /* ----- 页脚 ----- */
    .site-footer {
      background: #1F2329;
      color: rgba(255,255,255,0.7);
      padding: 48px 0 32px;
      border-radius: 24px 24px 0 0;
    }

    .footer-grid {
      display: flex;
      justify-content: space-between;
      flex-wrap: wrap;
      gap: 32px;
    }

    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
    }

    .footer-desc {
      max-width: 280px;
      margin-top: 12px;
      font-size: 14px;
    }

    .footer-links a {
      display: block;
      color: rgba(255,255,255,0.6);
      margin-bottom: 8px;
      font-size: 15px;
    }

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

    .copyright {
      margin-top: 40px;
      font-size: 14px;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
      text-align: center;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 36px; }
      .hero-visual { gap: 12px; }
    }

    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 20px 24px;
        box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      }
      .nav-menu.open { display: flex; }
      .menu-toggle { display: block; }
      .hero-grid { flex-direction: column; }
      .service-grid { grid-template-columns: 1fr; }
      .compare-grid { grid-template-columns: 1fr; }
    }

    @media (max-width: 520px) {
      .container { padding: 0 16px; }
      h1 { font-size: 30px; }
      h2 { font-size: 26px; }
      .btn-group { flex-direction: column; }
    }