How to remove square corners when border-radius is set in Qt?

I switched my whole stylesheet to border-radius: 10px to give my program a more modern appareance:

However, sometimes the rounded corners are against a black background and the result isn’t pretty:

Is there a way to remove the extraneous square corners? Here’s the stylesheet: https://github.com/Kobo-InkBox/inkbox/blob/5ad4e773661a56801712ea9d59adf6d54c1bbca4/resources/eink.qssdata

Welcome to the community, @madking2! Maybe a screenshot for your issue should also help the community to understand your issue pictorially.