Yep, a dark / night theme is on the list as a Supporter feature.
An error occurred while saving the commentPizzaTheHutt commented
Black text on white background seems to be easier to read, but I agree that this option to have white text on a black background would be a great option for extending battery life.
This can be done (I can add a text box in the catalogue editor). But bear in mind changing this is risky business and could break data in bad ways….