/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary-orange: #F04E23;
      --primary-orange-dark: #D13E1A;
      --deep-charcoal: #1A1A1A;
      --text-body: #4A4A4A;
      --text-muted: #8A8A8A;
      --bg-white: #FAFAFA;
      --bg-light-gray: #F2F2F2;
      --accent-cyan: #00C2BA;
      --card-shadow: 0 4px 16px rgba(0,0,0,0.04);
      --card-shadow-hover: 0 12px 28px rgba(0,0,0,0.08);
      --border-light: rgba(0,0,0,0.04);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-mono: 'Roboto Mono', 'DIN Alternate', 'Courier New', monospace;
    }
    
    * {
      box-sizing: border-box;
    }
    
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      background-color: var(--bg-white);
      color: var(--text-body);
      line-height: 1.7;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
    }
    
    /* 数字专用字体 */
    .font-mono, .stat-number, .data-highlight {
      font-family: var(--font-mono);
      font-weight: 700;
    }
    
    /* 容器 */
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    
    /* 导航条 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 50;
      border-bottom: 1px solid rgba(0,0,0,0.02);
      transition: background 0.3s ease, box-shadow 0.3s ease;
    }
    .navbar.scrolled {
      background: rgba(255,255,255,0.95);
      box-shadow: 0 2px 20px rgba(0,0,0,0.04);
    }
    
    .nav-link {
      color: var(--text-body);
      font-size: 0.95rem;
      font-weight: 500;
      position: relative;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0%;
      height: 2px;
      background-color: var(--primary-orange);
      transition: width 0.25s ease;
    }
    .nav-link:hover {
      color: var(--primary-orange);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    
    /* 按钮系统 */
    .btn-primary {
      background-color: var(--primary-orange);
      color: white;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      border: none;
      cursor: pointer;
      transition: background-color 0.2s, transform 0.2s, box-shadow 0.2s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background-color: var(--primary-orange-dark);
      transform: scale(1.03);
      box-shadow: 0 8px 18px rgba(240,78,35,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-orange);
      color: var(--primary-orange);
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      transition: background-color 0.2s, color 0.2s;
    }
    .btn-outline:hover {
      background-color: rgba(240,78,35,0.05);
    }
    
    /* 卡片样式 */
    .feature-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--card-shadow);
      border: 1px solid var(--border-light);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-shadow-hover);
    }
    .case-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--card-shadow);
      border-left: 4px solid var(--primary-orange);
      transition: border-left-width 0.2s, box-shadow 0.2s;
    }
    .case-card:hover {
      border-left-width: 8px;
      box-shadow: var(--card-shadow-hover);
    }
    
    /* 手风琴样式 */
    .faq-item {
      border-bottom: 1px solid rgba(0,0,0,0.06);
    }
    .faq-question {
      cursor: pointer;
      font-weight: 600;
      color: var(--deep-charcoal);
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-icon {
      color: var(--primary-orange);
      transition: transform 0.3s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    
    /* 数字递增动画相关 */
    .count-up {
      display: inline-block;
    }
    
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: white;
      padding: 24px;
      flex-direction: column;
      box-shadow: 0 20px 30px rgba(0,0,0,0.05);
      z-index: 49;
    }
    .mobile-menu.open {
      display: flex;
    }
    
    @media (max-width: 768px) {
      .container-custom {
        padding-left: 20px;
        padding-right: 20px;
      }
    }