May be you want more but we used this widget to achieve this: https://appstore.home.mendix.com/link/app/109716/Objectivity/CssClassSwitcher
Then based on the microflow determine if you are running local, test, accp or production and based on that we swich the color so I can see visually in what environment I am in.
Regards,
Ronald
Is such a theme switcher widget available for mendix native at runtime?