/* roulang page: index */
/* 设计变量与视觉宪章 */
    :root {
      --primary: #0EA5E9;
      --primary-hover: #0284C7;
      --accent: #8B5CF6;
      --accent-hover: #7C3AED;
      --dark: #1E293B;
      --dark-soft: #0F172A;
      --gray-bg: #F8FAFC;
      --gray-border: #E2E8F0;
      --text-main: #1E293B;
      --text-secondary: #475569;
      --text-muted: #64748B;
      --white: #FFFFFF;
      --card-shadow: 0 4px 24px rgba(0,0,0,0.06);
      --card-shadow-hover: 0 8px 32px rgba(0,0,0,0.12);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --transition: 0.3s ease;
    }
    
    * {
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--gray-bg);
      color: var(--text-main);
      line-height: 1.6;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
    }
    
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    
    /* 导航系统 */
    .navbar {
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(10px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.05);
      height: 72px;
      position: sticky;
      top: 0;
      z-index: 50;
    }
    .nav-link {
      color: #475569;
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
    }
    .nav-link:hover, .nav-link.active {
      color: #0EA5E9;
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 100%;
      height: 2px;
      background: #0EA5E9;
    }
    
    /* 卡片系统 */
    .card {
      background: white;
      border-radius: 16px;
      padding: 2rem;
      box-shadow: 0 4px 24px rgba(0,0,0,0.06);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
      height: 100%;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: 0 12px 36px rgba(0,0,0,0.1);
    }
    .solution-card {
      border-left: 4px solid #0EA5E9;
    }
    
    /* 按钮 */
    .btn-primary {
      background: #0EA5E9;
      color: white;
      padding: 14px 32px;
      border-radius: 8px;
      font-weight: 600;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: #8B5CF6;
      transform: scale(1.03);
    }
    .btn-outline {
      border: 1.5px solid #0EA5E9;
      color: #0EA5E9;
      background: transparent;
      padding: 14px 32px;
      border-radius: 8px;
      font-weight: 600;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
    }
    .btn-outline:hover {
      background: #E0F2FE;
      border-color: #0284C7;
      color: #0284C7;
    }
    
    /* 手风琴FAQ */
    .faq-item {
      border-bottom: 1px solid #E2E8F0;
    }
    .faq-question {
      cursor: pointer;
      padding: 1.2rem 0;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: #1E293B;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: #475569;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 1.2rem;
    }
    
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: rgba(30,41,59,0.95);
      backdrop-filter: blur(20px);
      flex-direction: column;
      align-items: center;
      padding: 2rem;
      z-index: 40;
    }
    .mobile-menu a {
      color: white;
      font-size: 1.5rem;
      margin: 1rem 0;
      font-weight: 500;
    }
    
    @media (max-width: 767px) {
      .container-custom {
        padding-left: 1rem;
        padding-right: 1rem;
      }
      h1 {
        font-size: 2rem !important;
      }
      h2 {
        font-size: 1.75rem !important;
      }
      .hide-mobile {
        display: none !important;
      }
      .mobile-menu.active {
        display: flex;
      }
    }
    
    /* 装饰元素 */
    .circuit-bg {
      background-image: radial-gradient(circle at 20% 30%, #0EA5E9 1px, transparent 1px);
      background-size: 40px 40px;
      opacity: 0.05;
    }