/* roulang page: index */
:root {
      --primary: #C8FF00;
      --primary-dark: #000000;
      --accent: #FF4D00;
      --dark-bg: #1A1C20;
      --card-bg: #FFFFFF;
      --body-bg: #F8F9FA;
      --text-primary: #1A1C20;
      --text-secondary: #4A4D52;
      --text-muted: #6C757D;
      --border-light: #E9ECEF;
      --shadow-card: 0 8px 20px rgba(0,0,0,0.02), 0 2px 6px rgba(0,0,0,0.04);
      --shadow-hover: 0 20px 30px rgba(0,0,0,0.06), 0 6px 12px rgba(0,0,0,0.05);
      --radius-xl: 1.5rem;
      --radius-2xl: 2rem;
      --transition-smooth: all 0.3s cubic-bezier(0.2, 0.0, 0.2, 1);
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
      background-color: var(--body-bg);
      color: var(--text-primary);
      line-height: 1.6;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      color: inherit;
      text-decoration: none;
      transition: var(--transition-smooth);
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 768px) {
      .container {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }
    /* 导航样式 */
    .header-nav {
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      position: sticky;
      top: 0;
      z-index: 50;
      transition: box-shadow 0.3s;
    }
    .header-nav.scrolled {
      box-shadow: 0 4px 12px rgba(0,0,0,0.03);
    }
    .nav-link {
      color: var(--text-secondary);
      font-weight: 500;
      padding: 0.5rem 0;
      position: relative;
      font-size: 0.95rem;
    }
    .nav-link:hover {
      color: var(--primary-dark);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: #1A1C20;
      font-weight: 600;
      border-radius: 9999px;
      padding: 0.65rem 1.75rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition-smooth);
      border: none;
      cursor: pointer;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: #1A1C20;
      color: var(--primary);
      transform: translateY(-1px);
      box-shadow: 0 8px 16px rgba(26,28,32,0.15);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid #1A1C20;
      color: #1A1C20;
      font-weight: 600;
      border-radius: 9999px;
      padding: 0.65rem 1.75rem;
      transition: var(--transition-smooth);
    }
    .btn-outline:hover {
      background: #1A1C20;
      color: white;
      border-color: #1A1C20;
    }
    /* 卡片悬停效果 */
    .card-hover {
      transition: var(--transition-smooth);
      background: white;
      border-radius: var(--radius-2xl);
      box-shadow: var(--shadow-card);
    }
    .card-hover:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    /* 数据徽章数字 */
    .stat-number {
      font-weight: 800;
      color: var(--primary);
      font-size: 2.8rem;
      line-height: 1.2;
    }
    @media (min-width: 768px) {
      .stat-number {
        font-size: 3.5rem;
      }
    }
    /* FAQ 动画 */
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, opacity 0.3s ease;
      opacity: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 300px;
      opacity: 1;
    }
    .faq-icon {
      transition: transform 0.3s ease;
      color: var(--primary-dark);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--accent);
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
    }
    @media (max-width: 767px) {
      .desktop-nav-links {
        display: none;
      }
      .mobile-menu {
        display: block;
      }
    }
    /* 自定义下划线装饰 */
    .section-title-decor {
      display: inline-block;
      position: relative;
      margin-bottom: 1.5rem;
    }
    .section-title-decor::before {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 48px;
      height: 4px;
      background: var(--primary);
      border-radius: 4px;
    }