Toggle between color themes

I’m looking for a way to include a button to toggle between dark and light themes. Is there currently support for including an additional dark mode theme to apps in Fliplet? I wish to programmatically change the theme settings directly so that the styles can be reflected in all pages across the entire app (our current implementation only applies theme settings for a singular page). There is documentation to reference theme-specific css variable values, however, can those variables be overridden? If so, what is the best way to go about this so that the changes are reflected on all pages.