jupyterlab/packages/apputils-extension/style/settingeditor.css

/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

#setting-editor.jp-SettingEditor {
  outline: none;
}


#setting-editor.jp-SettingEditor .jp-PluginList {
  background: yellow;
}


#setting-editor.jp-SettingEditor .jp-PluginEditor {
  background: blue;
}