Can the vertical bar separating panels in split screen view be modified?

The new mobile app on my iPad is a great step forward, and I particularly like having tabs.

I do, howver, find the vertical bar separating the panels in split screen view annoying when View Settings is set to low light. The thick bar is simply too bright and distracting to my eyes when the room is fairly dark at night.

A darker bar, such as dark gray, would be much better in my opinion (a thinner bar would also be nice), but I suspect that the design of the bar is built in.