In Keynote, how to change no-fill color from black to something else? Using MacOS Keynote, I'm exporting animated graphics with transparent backgrounds. For example, the graphic may be black and white such as this:

 

But to make the background of the slide transparent, the background is set to no-fill which causes the background to be black:



So to work with files with black text or artwork (everything I do), the background color must be repeatedly flipped between fill color and no-fill. Is there a way to set the default for the no-fill color to something else than black such as gray?:
Click on the object of interest and on top right click on format. The in the right sidebar click on style. The sidebar should look as shown below. Directly above the "No fill" pulldown is a box with a red diagonal line (shown with a blue rectangle around it). Click on that box and select your color.