[Q] Background color for Google Play Books with T700 topic

I use my Android tablets for reading, using Google Play Books. I prefer a bright white background. With my Nexus 7 (2013) it's a pure white background, just the way I like it. With the Tab S 8.4 I can't seem to achieve bright white. It's more like a light sepia. I know sepia is a choice but that's a very dark (to my eyes) background. I've also played around with the Screen Mode but none of the choices seem to change the GPB background at all. I've turned Reading Mode on and off but I don't see any difference.

I know there are other reading apps but I like having a large library stored in the Google cloud and the ability to switch devices and have the bookmark change with it.

Any suggestions on how to change the background color for just Google Play Books?