It would be ideal that it would be made “user adjustable” and saved in preferences somewhere however, just having a descent collection of typographic font pairings would really make the selecteed area pop!!
I’ve noticed that when I’m posting a lot of refrence clips from the web, going back and forth quickly trying to find the copy can be a task. There needs to be more visual contrast - even just adding one good typeface family with a heavy weight would be a great solution to start out with. The interface is almost there, love the minimal layout… good job!