I'm now proceeding to replacing SASS.
Is it possible to define a class without a selector? For example:
//
//Light on dark text
//
.light-on-dark{
color: $isa-light;
background-color: $isa-dark;
}
The $names are SASS and are defined earlier.

Are CSS variables supported. Could I define:
body{
--isa-light: white;
--isa-dark: purple;
}
.light-on-dark{
color: var(--isa-light);
background-color: (--isa-dark);
}
and just assign class light-on dark to an element?

Thanks, Tom

You need to convert SASS to CSS. AFAIK SD cannot handle SASS files.

As to classes without selectors, I've seen it has been done with js, I don't think it is possible to do it with css alone. For example, some of the Foundation building blocks include such things, like e.g. one called "Sticky Shrinknav Hero". In such a case, when the selectors are added and removed by js, both the css and the js has to be added in the page manager.