/* roulang page: index */
/* 自定义CSS变量与全局样式 */
    :root {
      --primary: #1A56DB;
      --primary-dark: #1E40AF;
      --accent: #F59E0B;
      --accent-dark: #D97706;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --text: #0F172A;
      --text-secondary: #64748B;
      --border-light: #E2E8F0;
      --shadow-card: 0 8px 20px rgba(0, 0, 0, 0.04), 0 2px 6px rgba(0, 0, 0, 0.02);
      --shadow-card-hover: 0 20px 30px rgba(0, 0, 0, 0.07), 0 6px 10px rgba(0, 0, 0, 0.03);
      --radius-xl: 16px;
      --radius-2xl: 20px;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.6;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
    }
    .container-main {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 768px) {
      .container-main {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }
    /* 导航栏 */
    .navbar {
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 4px rgba(0,0,0,0.02);
      border-bottom: 1px solid var(--border-light);
      position: sticky;
      top: 0;
      z-index: 50;
      height: 72px;
    }
    @media (min-width: 768px) {
      .navbar {
        height: 80px;
      }
    }
    .nav-link {
      font-size: 0.875rem;
      font-weight: 500;
      color: #334155;
      transition: color 0.2s ease;
      text-decoration: none;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .active-nav {
      color: var(--primary);
      font-weight: 600;
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(20px);
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 2rem;
      z-index: 40;
    }
    .mobile-menu.open {
      display: flex;
    }
    /* 按钮系统 */
    .btn-primary {
      background: linear-gradient(135deg, #1A56DB 0%, #2563EB 100%);
      color: white;
      padding: 0.75rem 2rem;
      border-radius: 0.75rem;
      font-weight: 600;
      box-shadow: 0 10px 15px -5px rgba(26,86,219,0.3);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
      display: inline-block;
      text-decoration: none;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: linear-gradient(135deg, #1E40AF 0%, #1D4ED8 100%);
      box-shadow: 0 15px 20px -6px rgba(26,86,219,0.4);
      transform: translateY(-2px);
    }
    .btn-outline {
      border: 2px solid var(--primary);
      color: var(--primary);
      background: transparent;
      padding: 0.75rem 2rem;
      border-radius: 0.75rem;
      font-weight: 600;
      transition: all 0.3s ease;
      display: inline-block;
      text-decoration: none;
      cursor: pointer;
    }
    .btn-outline:hover {
      background: #EFF6FF;
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-2xl);
      box-shadow: var(--shadow-card);
      border: 1px solid #f1f5f9;
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-6px);
    }
    .service-card {
      border-top: 4px solid transparent;
      border-image: linear-gradient(90deg, #1A56DB, #F59E0B) 1;
      border-radius: var(--radius-2xl) var(--radius-2xl) var(--radius-2xl) var(--radius-2xl);
      overflow: hidden;
    }
    .metric-number {
      color: var(--accent);
      font-weight: 800;
    }
    /* 动画 */
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }
    .animate-fadeInUp {
      animation: fadeInUp 0.6s ease forwards;
    }
    /* 手风琴 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease-in-out;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
    }
    .faq-icon {
      transition: transform 0.3s ease;
    }
    .faq-item.open .faq-icon {
      transform: rotate(180deg);
    }
    /* 进度条 */
    .progress-bar {
      height: 8px;
      background: #E2E8F0;
      border-radius: 10px;
      overflow: hidden;
    }
    .progress-fill {
      height: 100%;
      background: linear-gradient(90deg, #1A56DB, #2563EB);
      border-radius: 10px;
      width: 0%;
      transition: width 1.2s ease;
    }
    /* 背景装饰 */
    .hero-visual {
      background: radial-gradient(circle at 30% 40%, rgba(26,86,219,0.08) 0%, transparent 60%);
    }