I use light theme when it is bright outside and dark theme in the evening when even the lowest brightness setting on my laptop is too bright. These days I rarely do reviews late at night, but maybe during winter when there’s not much daylight I’ll probably use dark theme more often.
Btw, it’s kinda fun how going to reviews to change the theme even on the main page is faster than going to the main styling settings now that auto-update is live. 便利ですねー
Edit: Not so benri when there are no reviews available TuT