This code is provided to you, free of charge, by reddit user u/haukino. It's based on the suggestions by u/SevenMonkeyFury - Thanks for that! See discussion here: https://www.reddit.com/r/OneNote/comments/e3148m/invisible_equations_in_dark_mode_on2016/ Feel free to adapt it to your needs and share if you have any improvements.
It tackles the problem with math equations in onenote 2016 not being visible in dark mode.
It simply changes the pages background to a light colour and enters equation mode so you
can type away once you pressed the hotkey.