Questions & Answers about Gledalište je otvoreno.
Not exactly.
Gledalište usually means the auditorium, seating area, viewer area, or spectator section. In some contexts it can also mean the audience side of a theater.
Kazalište is the more general word for theater as a building or institution.
So Gledalište je otvoreno is more like The auditorium / viewing area is open, not necessarily The theater is open in the broadest sense.