If you try to insert variables (syntax: ‘–variable’) the checker will regard that as an error (“Expected RBRACE at …”). Could you please fix that? Thanks!
The error text mentioned does not occur in the WordPress core (not even in language files). Which CSS highlighting do you use and where? I have tried it in the Customizer at Additional CSS and get there at
I use the Divi Builder, the checker is included in their menu. But their support told me: “And that issue isn’t related to the Divi theme, it’s related to the WordPress syntax checker that needs to be updated in the WordPress itself.”
Unfortunately, I do not know Divi and, since it is a commercial product, I cannot judge what is used there and where. If Divi support could say more specifically which CSS checker it is (e.g. a filename of a WordPress-file which is used here), it would be easier to judge.