Aww you missed a nice queen pin that game. But yeah...no clue. Maybe they had to leave or something.
Why did my opponent just resign?!

If you had played 17...Rg5, your opponent's queen would not be able to escape capture from your rook. https://www.chess.com/terms/pin-chess

If you had played 17...Rg5, your opponent's queen would not be able to escape capture from your rook. https://www.chess.com/terms/pin-chess
Oooooooooooooopsie.
That's me in white backed into a corner, why resign?
Am I missing something? I admit it's late, I'm overtired, stupidly jacked up on caffeine and playing largely with my adrenals instead of my brain. Not a good idea, but I got away with it this particular game...