Dark Theme Preview Pane

I’m on 7.2.34030.0 free version. I think a recent update changed the color of the preview pane wrapper. I use the dark theme. The message background color is white, but the subject, header info, etc. is dark. There is no padding on the left. The entire preview pane used to be all white. This look with no padding really doesn’t suit me. Can I change the wrapper to be white like it was, somehow?