This problem could be solved with better editors. You could switch between "programmatic mode" (with all variables and fancy stuff) and "view source mode" (with variable values and plain CSS in general) with one keystroke.

You could also have semi-programmatic modes that show some programmatic features and "expand" others. Also it would be possible to look at the plain CSS but have values coming from the same variable in a distinct color.

We should get more creative with multiple views of the same document in the editing department.