/* roulang page: index */
:root {
      --primary: #1E40AF;
      --primary-light: #2563EB;
      --accent-cyan: #0EA5E9;
      --accent-indigo: #4F46E5;
      --bg-light: #F8FAFC;
      --bg-white: #FFFFFF;
      --bg-dark: #0B132B;
      --text-title: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-line: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.05);
      --shadow-md: 0 10px 25px -5px rgba(15, 23, 42, 0.04), 0 8px 10px -6px rgba(15, 23, 42, 0.02);
      --shadow-hover: 0 20px 35px -5px rgba(30, 64, 175, 0.12), 0 10px 15px -5px rgba(30, 64, 175, 0.04);
      --radius-base: 12px;
      --radius-large: 16px;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      color: var(--text-body);
      background-color: var(--bg-light);
    }

    body {
      line-height: 1.65;
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: inherit;
      text-decoration: none;
      transition: all 0.25s ease;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    /* 容器基准 */
    .site-container {
      width: 100%;
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.25rem;
      padding-right: 1.25rem;
    }

    @media (min-width: 1024px) {
      .site-container {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }

    /* 板块通用间距 */
    .section-py {
      padding-top: 5rem;
      padding-bottom: 5rem;
    }

    @media (max-width: 768px) {
      .section-py {
        padding-top: 3.5rem;
        padding-bottom: 3.5rem;
      }
    }

    /* 卡片标准阴影与过渡 */
    .card-modern {
      background: var(--bg-white);
      border: 1px solid var(--border-line);
      border-radius: var(--radius-large);
      box-shadow: var(--shadow-md);
      transition: transform 0.28s ease, box-shadow 0.28s ease, border-color 0.28s ease;
    }

    .card-modern:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(37, 99, 235, 0.3);
    }

    /* 推荐高亮选型卡片 */
    .card-featured-tier {
      background: #FFFFFF;
      border: 2px solid var(--primary-light);
      border-radius: var(--radius-large);
      box-shadow: 0 15px 30px -5px rgba(37, 99, 235, 0.18);
      position: relative;
    }

    /* 按钮规范 */
    .btn-primary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background-color: var(--primary-light);
      color: #FFFFFF;
      font-weight: 600;
      padding: 0.75rem 1.75rem;
      border-radius: 8px;
      transition: all 0.25s ease;
      box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
      border: none;
      cursor: pointer;
    }

    .btn-primary:hover {
      background-color: var(--primary);
      box-shadow: 0 6px 18px rgba(30, 64, 175, 0.35);
      transform: translateY(-1px);
    }

    .btn-secondary {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background-color: #FFFFFF;
      color: var(--primary);
      font-weight: 600;
      padding: 0.75rem 1.75rem;
      border-radius: 8px;
      border: 1px solid var(--border-line);
      transition: all 0.25s ease;
      cursor: pointer;
    }

    .btn-secondary:hover {
      background-color: #F1F5F9;
      border-color: #CBD5E1;
      color: var(--primary-light);
    }

    /* 标签徽章 */
    .badge-tag {
      display: inline-flex;
      align-items: center;
      padding: 0.25rem 0.75rem;
      font-size: 0.8125rem;
      font-weight: 600;
      border-radius: 9999px;
      background: rgba(14, 165, 233, 0.1);
      color: var(--primary-light);
      border: 1px solid rgba(14, 165, 233, 0.2);
    }

    /* 导航栏双行样式 */
    .top-subnav {
      background-color: #F1F5F9;
      border-bottom: 1px solid var(--border-line);
      font-size: 0.8125rem;
      color: var(--text-muted);
    }

    .main-navbar {
      background-color: #FFFFFF;
      box-shadow: var(--shadow-sm);
      position: sticky;
      top: 0;
      z-index: 50;
      backdrop-filter: blur(8px);
    }

    /* 滚动条美化 */
    ::-webkit-scrollbar {
      width: 8px;
      height: 8px;
    }
    ::-webkit-scrollbar-track {
      background: #F1F5F9;
    }
    ::-webkit-scrollbar-thumb {
      background: #CBD5E1;
      border-radius: 4px;
    }
    ::-webkit-scrollbar-thumb:hover {
      background: #94A3B8;
    }