I was playing ACNL for about 2 hours last night but today I woke up and when I opened Citra it was just the sounds of the game and a blank screen. I have already tried to reinstall Citra and AC. Didn’t work.
I had a similar problem last night trying to get Citra to work on my Mac. Toggling the size only changed the screen from grey to black. DO NOT turn on hardware shader or accurate multiplication on a Mac. You will get an error message “Hardware Shader support is broken on MacOS and will cause graphical issues like showing a black screen”