As title asks, is it possible to bind the style of a mashup to a boolean value of a thing?
I want my mashup to be red if my_bool= false and green if my_bool=true.
With the use of state based formatting you can drive the color formatting of your widgets.
That can't be done with a mashup background, however you could use a contained mashup technique to swap out mashups to achieve a full mashup color change effect.
or you could use a shape but that means layering widgets and that is not responsive.