/* roulang page: index */
/* 设计变量与基础重置 */
    :root {
      --primary: #D32F2F;
      --primary-dark: #B71C1C;
      --secondary: #1A1A1A;
      --accent: #FFB300;
      --bg: #FAFAFA;
      --card-bg: #FFFFFF;
      --deep-bg: #212121;
      --text-main: #1A1A1A;
      --text-soft: #4a4a4a;
      --border-light: #e5e7eb;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 4px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.12);
      --transition: all 0.25s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
      line-height: 1.75;
      background-color: var(--bg);
      color: var(--text-main);
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      transition: var(--transition);
    }
    /* 导航滚动效果 */
    .navbar-scrolled {
      background-color: #1A1A1A !important;
      box-shadow: 0 1px 6px rgba(0,0,0,0.2);
    }
    .navbar-transparent {
      background-color: rgba(26,26,26,0.85);
      backdrop-filter: blur(8px);
    }
    /* 卡片hover微交互 */
    .card-hover {
      transition: var(--transition);
      border-bottom: 3px solid transparent;
    }
    .card-hover:hover {
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
      border-bottom-color: var(--primary);
    }
    @media (hover: none) {
      .card-hover:hover {
        transform: none;
        box-shadow: var(--shadow-sm);
        border-bottom-color: transparent;
      }
    }
    /* 手风琴动画 */
    .faq-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
    }
    .faq-item.active .faq-content {
      max-height: 200px;
      padding-top: 0.75rem;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--primary);
    }
    .faq-icon {
      transition: transform 0.3s ease, color 0.2s;
    }
    /* 移动端菜单 */
    .mobile-menu {
      transform: translateX(100%);
      transition: transform 0.35s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    /* 装饰线条 */
    .brand-left-line {
      border-left: 4px solid var(--primary);
      padding-left: 1.25rem;
    }
    .accent-underline {
      background: linear-gradient(to right, var(--primary), var(--accent));
      height: 3px;
      width: 60px;
      margin: 0.5rem 0 1rem;
    }
    /* 按钮样式 */
    .btn-primary {
      background-color: var(--primary);
      color: white;
      border-radius: var(--radius-btn);
      padding: 0.75rem 2rem;
      font-weight: 600;
      border: none;
      box-shadow: 0 2px 6px rgba(211,47,47,0.3);
    }
    .btn-primary:hover {
      background-color: var(--primary-dark);
      box-shadow: 0 4px 12px rgba(183,28,28,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 0.65rem 1.75rem;
      font-weight: 600;
    }
    .btn-outline:hover {
      background-color: rgba(211,47,47,0.08);
    }
    .btn-accent {
      background-color: var(--accent);
      color: #1A1A1A;
      font-weight: 700;
      border-radius: var(--radius-btn);
      padding: 0.85rem 2.2rem;
      border: none;
      box-shadow: 0 4px 10px rgba(255,179,0,0.3);
    }
    .btn-accent:hover {
      background-color: #ffb300e6;
      box-shadow: 0 6px 14px rgba(255,179,0,0.45);
    }
    /* 统计数字强调 */
    .stat-number {
      color: var(--accent);
      font-weight: 800;
    }
    /* 响应式额外调整 */
    @media (max-width: 768px) {
      h1 {
        font-size: 2.25rem;
      }
      h2 {
        font-size: 1.8rem;
      }
      .mobile-menu {
        display: block;
      }
    }