I would like to know how to change the color of the top of an interstate shield text symbol in ArcGIS Pro. The default interstate shield symbol is a blue shield with a red top. In the text symbol properties, it is easy to change the bottom of the shield from blue to another color (see screenshot). How can I change the top of the shield? I am able to do this in ArcMap but can't identify how to do it in ArcGIS Pro (2.1.0).
I want interstates labeled, but want the labels to be more muted, so I am trying to make them gray instead of colored.