Does writing on GDocs have your eyeballs feeling a "closeup in Spongebob" sort of way? Try this!
First, install the Stylus extension if you haven't already. Remember, though, to get Stylus and not Stylish as the latter was bought out and injected with spyware. That's a whole can of worms you can read about if you're curious because it does present some grave dangers in being lackadaisical about your browser setup.
Anywho… Now that that's out of the way, create a new stylesheet for URLs starting with https://docs.google.com/document/
. In there drop this small bit of CSS:
.kix-appview-editor {
background-color: #2e3440 !important;
}
This turns the area around the document from nearly-white to a cool blue-tinged gray. Yes, the document itself is still bright, but it being surrounded by darker colors is welcome eyeball relief.

There is an extension (or three) that strives to give GDocs a proper dark mode, but I couldn't be bothered to check it out. I want to see how the documents actually look when sent to others. Because, like, if I'm using GDocs at all then it's because I'm writing something for someone else to read.
All of my personal notes and whatnot are elsewhere; I don't want a corporation snooping through all of my personal shit ⸺ even if that shit is boring. You still have a right to privacy (for now), so you might as well use it!