/* 控制头部左右两端对齐 */
    .header {
      display: flex;
      justify-content: space-between; /* 将标题和按钮推向两端 */
      align-items: center; /* 垂直方向居中对齐 */
      margin-bottom: 20px; /* 和下方的元信息拉开距离 */
    }

    .header h2 {
      margin: 0; /* 消除 h2 默认的上下边距，保持整洁 */
      font-size: 2em;
    }

    /* 稍微美化一下关闭按钮 */
    .back-btn {
      color: inherit;
      text-decoration: none;
      font-size: 0.9em;
      opacity: 0.7;
      transition: opacity 0.3s;
    }

    .back-btn:hover {
      opacity: 1;
      text-decoration: underline; /* 鼠标悬浮时加个下划线提示 */
    }