/* roulang page: index */
/* ----- 自定义CSS：完整设计系统与视觉套装 ----- */
    :root {
      /* 主色系：沉静商务蓝 */
      --primary: #1A3C6D;
      --primary-hover: #152E54;
      --primary-light: #F0F4FA;
      
      /* 辅色系：暖金色点缀 */
      --accent: #C9A96E;
      --accent-dark: #B28A4A;
      
      /* 背景与表面 */
      --bg-page: #F8F9FB;
      --bg-card: #FFFFFF;
      --border-light: #E9ECEF;
      --border-card: #E9ECEF;
      
      /* 文字层级 */
      --text-h1: #1A1A1A;
      --text-heading: #1A1A1A;
      --text-body: #4A4A4A;
      --text-muted: #6B7280;
      --text-footer: #B0B8C1;
      --text-footer-light: #8A94A6;
      --bg-dark: #1A1A1A;
      
      /* 形状与阴影 */
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-nav: 0 2px 8px rgba(0,0,0,0.02);
      
      /* 间距与排版 */
      --section-gap: 80px;
      --nav-height: 72px;
      --font-system: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', 'Inter', system-ui, -apple-system, sans-serif;
      
      /* 过渡 */
      --transition-base: 0.25s ease;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    body {
      font-family: var(--font-system);
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    
    h1, h2, h3, h4 {
      font-family: var(--font-system);
      color: var(--text-heading);
      margin-bottom: 1rem;
      letter-spacing: -0.3px;
    }
    
    h1 { font-size: 32px; font-weight: 700; letter-spacing: -0.5px; }
    h2 { font-size: 26px; font-weight: 700; }
    h3 { font-size: 20px; font-weight: 600; }
    
    .subhead {
      font-size: 16px;
      color: var(--text-muted);
      margin-bottom: 2rem;
    }
    
    a {
      color: var(--primary);
      text-decoration: none;
      transition: color var(--transition-base);
    }
    
    a:hover {
      color: var(--primary-hover);
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* 板块通用间距 */
    section {
      padding: var(--section-gap) 0;
    }
    
    @media (max-width: 640px) {
      section {
        padding: 48px 0;
      }
      h1 { font-size: 28px; }
      h2 { font-size: 22px; }
      h3 { font-size: 18px; }
    }
    
    /* ----- 导航系统 sticky + 毛玻璃 ----- */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(248, 249, 251, 0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      box-shadow: var(--shadow-nav);
      height: var(--nav-height);
      display: flex;
      align-items: center;
    }
    
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .logo-area {
      display: flex;
      align-items: baseline;
      gap: 10px;
    }
    
    .logo-text {
      font-size: 22px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.3px;
    }
    
    .logo-domain {
      font-size: 12px;
      color: var(--text-muted);
      letter-spacing: 0.3px;
      margin-left: 4px;
    }
    
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
      margin: 0;
    }
    
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      font-size: 15px;
      padding: 8px 0;
      position: relative;
      transition: color var(--transition-base);
    }
    
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 100%;
      height: 3px;
      background-color: var(--accent);
      border-radius: 2px;
    }
    
    /* 汉堡菜单 (Foundation responsive menu 定制) */
    .menu-icon {
      display: none;
      cursor: pointer;
      font-size: 24px;
      color: var(--primary);
    }
    
    @media (max-width: 840px) {
      .menu-icon {
        display: block;
      }
      .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 20px 24px;
        gap: 18px;
        box-shadow: 0 12px 24px rgba(0,0,0,0.08);
        border-bottom: 1px solid var(--border-light);
        z-index: 99;
      }
      .nav-links.show {
        display: flex;
      }
      .nav-links a {
        font-size: 18px;
        padding: 10px 0;
        border-bottom: 1px solid var(--border-light);
        width: 100%;
      }
      .nav-links a.active::after {
        display: none;
      }
    }
    
    /* ----- 按钮系统 ----- */
    .btn {
      display: inline-block;
      border-radius: var(--radius-sm);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: background var(--transition-base), border var(--transition-base), color var(--transition-base);
      text-align: center;
      border: 2px solid transparent;
    }
    
    .btn-primary {
      background-color: var(--primary);
      color: white;
      border-color: var(--primary);
    }
    
    .btn-primary:hover {
      background-color: var(--primary-hover);
      border-color: var(--primary-hover);
      color: white;
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    
    .btn-outline:hover {
      background-color: var(--primary-light);
      color: var(--primary);
    }
    
    .btn-lg {
      padding: 14px 36px;
      font-size: 17px;
      border-radius: 10px;
    }
    
    /* ----- Hero 双栏布局 ----- */
    .hero-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 40px;
      align-items: center;
    }
    
    .hero-content h1 {
      margin-bottom: 16px;
    }
    
    .hero-actions {
      display: flex;
      gap: 16px;
      margin-top: 28px;
      flex-wrap: wrap;
    }
    
    .hero-image img {
      border-radius: var(--radius-md);
      box-shadow: 0 20px 35px rgba(26, 60, 109, 0.1);
      width: 100%;
    }
    
    .trust-strip {
      display: flex;
      gap: 32px;
      margin-top: 32px;
      flex-wrap: wrap;
      color: var(--text-muted);
      font-size: 14px;
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-actions {
        justify-content: center;
      }
      .trust-strip {
        justify-content: center;
      }
    }
    
    /* ----- 亮点网格 2x3 ----- */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    
    .feature-card {
      background: var(--bg-card);
      border: 1px solid var(--border-card);
      border-radius: var(--radius-md);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition-base), box-shadow var(--transition-base);
    }
    
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    
    .feature-icon {
      width: 56px;
      height: 56px;
      background: var(--primary-light);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 640px) {
      .features-grid { grid-template-columns: 1fr; }
      .feature-card:hover { transform: none; border-color: var(--primary); }
    }
    
    /* ----- 方案对比卡 三列 ----- */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    
    .plan-card {
      background: var(--bg-card);
      border: 1px solid var(--border-card);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      position: relative;
      display: flex;
      flex-direction: column;
    }
    
    .plan-card.recommended {
      border-color: var(--accent);
      box-shadow: 0 6px 20px rgba(201,169,110,0.15);
    }
    
    .badge-recommend {
      position: absolute;
      top: -12px;
      right: 20px;
      background: var(--accent);
      color: white;
      padding: 4px 16px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
    }
    
    .plan-features {
      list-style: none;
      margin: 20px 0;
      flex: 1;
    }
    
    .plan-features li {
      padding: 8px 0;
      border-bottom: 1px solid var(--border-light);
      color: var(--text-body);
    }
    
    .plan-features i {
      color: var(--accent);
      margin-right: 8px;
    }
    
    @media (max-width: 768px) {
      .pricing-grid { grid-template-columns: 1fr; }
    }
    
    /* ----- 案例瀑布流 双列不等高 ----- */
    .cases-masonry {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 28px;
    }
    
    .case-card {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition-base), box-shadow var(--transition-base);
      display: flex;
      flex-direction: column;
    }
    
    .case-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    
    .case-img {
      position: relative;
      overflow: hidden;
      aspect-ratio: 16/9;
    }
    
    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      border-radius: 8px 8px 0 0;
      transition: transform 0.4s ease;
    }
    
    .case-card:hover .case-img img {
      transform: scale(1.03);
    }
    
    .case-info {
      padding: 20px;
    }
    
    .case-tags {
      display: flex;
      gap: 8px;
      margin: 10px 0;
      flex-wrap: wrap;
    }
    
    .tag {
      background: var(--primary-light);
      color: var(--primary);
      padding: 2px 10px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 500;
    }
    
    @media (max-width: 640px) {
      .cases-masonry { grid-template-columns: 1fr; }
    }
    
    /* ----- 数据信任带 ----- */
    .trust-stats {
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
      gap: 24px;
    }
    
    .stat-item h3 {
      font-size: 34px;
      color: var(--primary);
      margin-bottom: 8px;
    }
    
    /* ----- FAQ 手风琴定制 ----- */
    .accordion-item {
      border-bottom: 1px solid var(--border-light);
    }
    
    .accordion-title {
      font-size: 18px;
      font-weight: 600;
      padding: 18px 0;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-heading);
    }
    
    .accordion-title i {
      transition: transform 0.3s ease;
    }
    
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      color: var(--text-body);
      padding: 0 0;
    }
    
    .accordion-item.active .accordion-content {
      max-height: 200px;
      padding: 0 0 16px 0;
    }
    
    .accordion-item.active .accordion-title i {
      transform: rotate(180deg);
    }
    
    /* ----- CTA 横幅 ----- */
    .cta-banner {
      background: linear-gradient(135deg, #F0F4FA 0%, #FFFFFF 100%);
      border-radius: var(--radius-lg);
      padding: 60px 40px;
      text-align: center;
      border: 1px solid var(--border-light);
    }
    
    /* ----- 页脚深色主题 ----- */
    .site-footer {
      background: var(--bg-dark);
      color: var(--text-footer);
      padding: 60px 0 30px;
    }
    
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
    }
    
    .footer-logo {
      font-size: 26px;
      font-weight: 700;
      color: white;
    }
    
    .footer-links h4 {
      color: white;
      margin-bottom: 20px;
    }
    
    .footer-links a {
      color: var(--text-footer-light);
      display: block;
      margin-bottom: 10px;
    }
    
    .footer-links a:hover {
      color: var(--accent);
    }
    
    .copyright {
      border-top: 1px solid #2A2A2A;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }
    
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 500px) {
      .footer-grid { grid-template-columns: 1fr; }
    }
    
    /* 辅助类 */
    .text-center { text-align: center; }
    .mb-2 { margin-bottom: 2rem; }
    .color-accent { color: var(--accent); }