john79 - Hello. I use this Google Docs Dark Mode https://chrome.google.com/webstore/detail/google-docs-dark-mode-20/ihkdedfdcocppnnaiigjpckhegifagfd . That's the best one currently available. So click the link and you will find the best possible extension like this. I hope it helps you.

karl9 - I've just installed it and I will surely use it from now on. Looks nice, and doesn't slow down my browser- it is more than enough for me.