There is also this Dark Reader If you use chrome.
It gives you dark mode on whole browser and and can be switched on and off easily with button at top of browser (the icon that looks like 2 red eyes top right). Only issue is that it does slow browser responce by about .5 to 1 sec on my system. here is a screen shot,
adds dark mode to Home Assistant as well! This is what it looks like with the default Home Assistant Theme active. The look changes depending on what theme you are using. So if you have 6 custom themes , when you turn on dark mode you have 6 more variations without changing any code in ha (Bonus).
