/* roulang page: index */
/* === 设计宪法 :root 变量 (--yq- 命名空间) === */
    :root {
      --yq-primary: #1E7E34;
      --yq-primary-hover: #166B2A;
      --yq-primary-soft: rgba(30, 126, 52, 0.08);
      --yq-secondary: #D4A843;
      --yq-dark: #1E1E1E;
      --yq-body-text: #3A3A3A;
      --yq-muted: #5C6B5E;
      --yq-bg: #FAFBF7;
      --yq-card-bg: #FFFFFF;
      --yq-border: #E2E8E4;
      --yq-light-bg: #F7FAF5;
      
      --yq-radius-card: 12px;
      --yq-radius-btn: 8px;
      --yq-shadow-card: 0 4px 14px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.02);
      --yq-shadow-card-hover: 0 12px 28px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.02);
      --yq-shadow-btn-glow: 0 6px 18px rgba(30,126,52,0.3);
      
      --yq-font-sans: 'Inter', 'Noto Sans SC', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
      --yq-transition: 0.2s ease;
    }
    
    /* === 全局基础重置 === */
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    
    body {
      font-family: var(--yq-font-sans);
      line-height: 1.6;
      color: var(--yq-body-text);
      background-color: var(--yq-bg);
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }
    
    /* 容器定义 */
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
      width: 100%;
    }
    
    /* 链接默认行为 */
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--yq-transition);
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    /* 字体层级全局定义 */
    h1 { font-size: 2.25rem; line-height: 1.25; font-weight: 800; letter-spacing: -0.5px; color: var(--yq-dark); }
    h2 { font-size: 1.75rem; line-height: 1.3; font-weight: 700; color: var(--yq-dark); }
    h3 { font-size: 1.25rem; line-height: 1.4; font-weight: 600; color: var(--yq-dark); }
    h4 { font-size: 1.1rem; line-height: 1.5; font-weight: 600; }
    
    /* 区块间距 */
    .section {
      padding: 100px 0;
    }
    
    /* 卡片基础类 */
    .card {
      background: var(--yq-card-bg);
      border-radius: var(--yq-radius-card);
      box-shadow: var(--yq-shadow-card);
      transition: transform var(--yq-transition), box-shadow var(--yq-transition);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--yq-shadow-card-hover);
    }
    
    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--yq-radius-btn);
      transition: all var(--yq-transition);
      cursor: pointer;
      border: 1.5px solid transparent;
      padding: 14px 32px;
      font-size: 1rem;
      text-align: center;
      line-height: 1.2;
    }
    .btn-primary {
      background: var(--yq-primary);
      color: white;
      border-color: var(--yq-primary);
    }
    .btn-primary:hover {
      background: var(--yq-primary-hover);
      border-color: var(--yq-primary-hover);
      box-shadow: var(--yq-shadow-btn-glow);
    }
    .btn-outline {
      background: transparent;
      color: var(--yq-primary);
      border-color: var(--yq-primary);
    }
    .btn-outline:hover {
      background: var(--yq-primary-soft);
    }
    
    /* 导航栏 */
    .yq-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: white;
      z-index: 1000;
      border-bottom: 1px solid transparent;
      transition: border-color 0.2s;
    }
    .yq-header.scrolled {
      border-bottom-color: var(--yq-border);
    }
    .nav-logo {
      font-weight: 800;
      font-size: 1.5rem;
      color: var(--yq-dark);
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: var(--yq-primary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 1.2rem;
      font-weight: 700;
    }
    .nav-link {
      font-weight: 500;
      color: var(--yq-dark);
      padding: 0.5rem 1rem;
      border-radius: 6px;
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--yq-primary);
    }
    
    /* 汉堡菜单 */
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--yq-dark);
      cursor: pointer;
    }
    
    /* 移动端导航面板 */
    .mobile-nav {
      display: none;
      position: absolute;
      top: 72px;
      left: 0;
      width: 100%;
      background: white;
      box-shadow: 0 8px 20px rgba(0,0,0,0.05);
      flex-direction: column;
      padding: 20px;
    }
    .mobile-nav.active {
      display: flex;
    }
    
    /* FAQ 手风琴 */
    details.faq-item {
      background: var(--yq-card-bg);
      border: 1px solid var(--yq-border);
      border-radius: 12px;
      margin-bottom: 12px;
      padding: 18px 24px;
      transition: background 0.2s;
    }
    details.faq-item[open] {
      background: var(--yq-light-bg);
    }
    summary.faq-question {
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    summary.faq-question::-webkit-details-marker { display: none; }
    .faq-answer {
      margin-top: 12px;
      color: var(--yq-muted);
    }
    
    /* 数据指标样式 */
    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--yq-primary);
      line-height: 1.1;
    }
    
    /* 步骤装饰 */
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--yq-primary);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 1.3rem;
    }
    
    /* CTA 渐变背景 */
    .cta-gradient {
      background: linear-gradient(135deg, #1E7E34 0%, #145523 100%);
    }
    
    /* 页脚 */
    .footer-link-title {
      color: var(--yq-secondary);
      font-weight: 600;
      margin-bottom: 1rem;
    }
    
    /* 响应式处理 */
    @media (max-width: 1024px) {
      .section { padding: 80px 0; }
      .desktop-nav { display: none; }
      .hamburger { display: block; }
      .grid-4, .grid-3 { grid-template-columns: repeat(2, 1fr); }
    }
    
    @media (max-width: 768px) {
      h1 { font-size: 1.75rem; }
      h2 { font-size: 1.5rem; }
      .stat-number { font-size: 2.25rem; }
      .btn { padding: 12px 24px; width: 100%; }
      .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
      .section { padding: 64px 0; }
      .hero-flex { flex-direction: column; }
    }