Viewing Files Documents in ‘Dark Mode’

this has probably been mentioned before but I just wanted to share a cool way to view files using a ‘dark mode’ of sorts. by going to ‘accessibility' in settings, then going to ‘display & text size’ and enabling classic invert, when you go on the files app and view some pdfs that are too bright to look at at night for example, the background will be black instead of white. this helped me to read books online without straining my eyes too much. hope this is able to help someone!