Changing Menubar Background Color & Text Color

I would like to change the background to a darker color and use white text.

Is this possible for Mac and WIndows using declares?

On Mac the user controls that with the Dark setting in System Preferences > General.

Thanks Tim but I want the user to be able to control themes manually via my app so need to know whether it is possible to handle through declares on both platforms.

Following… need to know this too

Under Windows : https://forum.xojo.com/30904-windows-10-window-titlebar-color

On Windows, it can be alright since the menu is part of the application windows.

On Mac, I believe changing the menu bar would not be quite HIG compliant. Personally, I would terribly much resent a program that changes the color of the menu bar, the dock, or anything else on MY desktop.