Quick PS question

Does anyone know how to change the background color in full mode? (ie press ‘f’ once and you can go into a mode that lets you drag the art-board around [has a gray bg] rather than being limited, once more and it puts you in preview mode with a black bg., a third takes you back to regular)

i must have mashed some keys and now instead of the normal gray bg it is black just like the preview mode, it’s harder to work in when black because it messes up color perception.

anyways, if someone knows the trick to set it back to normal i would appreciate it. I have already tried setting workspace to default but that is just the panel setup not the actual background.