i am not sure that understand 100% your question. 1920x1080, but the size of maximized window is accordingly pc monitor resolution.
did you change something again? i was away for a few days and i entered the site today. it seems roll back. No fluid in browsers windowd mode again.
I did not work with your site before that, you can change again
also, i checked this block the same for the resolution prntscr.com/n3hz6fprntscr.com/n3hzsk