Highlight the Layer group that is selected in web maps/apps

[lwilcock1]

I use a lot of layer groups to organize layer on a theme. It helps my viewers not feel overwhelmed and directs them to a more specific area. Since the grouped layers are nested under a group that needs to be clicked on to be visible, the visible group needs to be highlighted. In the example above, "Affordability" would have a dark grey header, and the layers in that group would have a light grey.