You can always copy them from css preview and paste into advanced section input.Thank you, Bogdan!
I think this could be solved by having multiple copy options, e.g. "copy with CSS variables"Alternatively you might show an equalent to such a dialog that wants to prevent exact duplicates in an image-database.
what would be making it more obvious?Puh, honestly this is hard to get across with a single line slit and your already introduced convention to add single properties with +.