Some people posted options for Linux and Mac, and the Windows (free) equivalent is, if you can deal with it globally:
Set Windows desktop appearance theme window background color. You can keep current/desired theme, just modify the background color of windows. By default, it is set to white. I change it to a shade of grey. I tried dark grey and black before, but then you have to change text font colors globally, and all that's painful.
But a simple shade of grey as background does the trick globally, works with any color text font as long as the shade of grey is not too dark.
It's not the best solution for all editors/IDEs, as I prefer black, but it's the next best free & global workaround on Windows.