body {
      min-height: 200vh;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    }

    /* 容器：固定在页面右侧中部 */
    .right-sidebar {
    position: fixed;
    right: 16px;
    top: 30%;
    z-index: 999;
    }

    /* 加号：锚点 */
    .toggle-btn {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: none;
    background: #111827;
    color: white;
    font-size: 28px;
    cursor: pointer;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    position: relative;
    z-index: 2;
    }

    /* 面板：绝对定位，从加号下方展开 */
    .panel {
    position: absolute;
    top: 56px;           /* 48px 按钮高度 + 间距 */
    right: 0;
    width: 100px;
    background: #fff;
    border-radius: 14px;
    padding: 10px;
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.18);

    display: none;
    }

    .panel.open {
    display: block;
    }


    /* 关闭按钮 */
    .close {
      text-align: right;
      margin-bottom: 8px;
    }

    .close button {
      background: none;
      border: none;
      font-size: 16px;
      cursor: pointer;
      color: #6b7280;
    }

    /* 入口按钮 */
    .nav-item {
      display: block;
      padding: 10px 12px;
      margin-bottom: 6px;
      border-radius: 12px;
      text-decoration: none;
      color: #111827;
      font-size: 14px;
      transition: background 0.2s;
    }

    .nav-item:hover {
      background: #f3f4f6;
    }