How to disable the violet gradient-heavy theme on Windows?

https://commons.wikimedia.org/wiki/File:Inkscape_0.47.png
I used to disable visual themes in the exe properties but the options are now greyed out. "Now" or it's because those compatibility options are not available for 64-bit exe files, I don't know.

Any solution is fine by me, but I would really like to avoid high-contrast theming or alterative icon sets if possible, as in the popular dark theme.