@font-face {
      font-family: 'OpenAISans-Medium';
      src: url('/font/openai/OpenAISans-Medium.woff2') format('woff2');
    }
    @font-face {
      font-family: 'OpenAISans-Regular';
      src: url('/font/openai/OpenAISans-Regular.woff2') format('woff2');
    }
    @font-face {
      font-family: 'OpenAISans-Semibold';
      src: url('/font/openai/OpenAISans-Semibold.woff2') format('woff2');
    }

    body {
      font-family: 'OpenAISans-Regular', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', Helvetica, Arial, sans-serif;
      background-color: #f9f9f9;
      color: #1c1c1e;
    }

    h1, h2, h3, h4, h5, h6 {
      font-family: 'OpenAISans-Semibold';
    }

    .level-bg-0 { background-color: #ffffff; }
    .level-bg-1 { background-color: #f2f2f7; }
    .level-bg-2 { background-color: #e5e5ea; }
    .level-bg-3 { background-color: #d1d1d6; }
    .level-bg-4 { background-color: #c7c7cc; }
    .level-bg-5 { background-color: #aeaeb2; }
    .level-bg-6 { background-color: #a5a5aa; }
    .tree-node {
      cursor: pointer;
      padding: 6px 10px;
      border-radius: 8px;
      transition: background 0.2s ease;
    }

    .tree-node:hover {
      background-color: #e5e5ea;
    }

    .toast {
      position: fixed;
      bottom: 20px;
      left: 50%;
      transform: translateX(-50%);
      background-color: #1c1c1e;
      color: #ffffff;
      padding: 10px 20px;
      border-radius: 8px;
      opacity: 0;
      transition: opacity 0.3s ease;
      z-index: 1000;
    }

    .toast.show {
      opacity: 1;
    }

    mark {
      background-color: #ffeeba;
      color: #000;
      padding: 0 2px;
      border-radius: 2px;
    }

    .no-result {
      text-align: center;
      margin-top: 1rem;
      color: #999;
      font-size: 0.9rem;
    }

    footer {
      margin-top: 3rem;
      padding: 1rem;
      text-align: center;
      font-size: 0.85rem;
      color: #666;
      background-color: #f3f4f6;
      border-top: 1px solid #ddd;
      border-radius: 8px;
    }

    .nav-logo {
      /* width: 32px; */
      height: 50px;
      margin-right: 10px;
      font-weight: bold;
    }

    /* 自定义响应式辅助类 */
    .responsive-text {
      font-size: clamp(0.8rem, 0.8vw + 0.8rem, 1.1rem);
    }

    .mobile-hide {
      display: none;
    }

    @media (max-width: 767px) {
      .mobile-hide {
        display: block !important;
      }
    }