Change background color/formatting in Gantt chart from Microsoft

Hi I am Gantt add-in visual from Mocrosoft in my report and am having difficulty in changing the background and font color of Category labels present there.

As can bee seen my background is black/dark blue and I want my labels/axis to be transparent or of same color as my background so that they can be integrated together. I searched in formatting options but wasn't able to find any option through which I can change these colors.

Does anybody have any idea, how to get it done? Thanks