With the latest JupyterLab 3.6.1 colours which were off-white are now black which makes them very difficult to distinguish on the dark background <table> <tr><th>JupyterLab 3.6.1</th></tr> <tr><td>  </td></tr> </table> <table> <tr><th>JupyterLab 3.5.2</th></tr> <tr><td>  </td></tr> </table>
With the latest JupyterLab 3.6.1 colours which were off-white are now black which makes them very difficult to distinguish on the dark background