I've had a lot of fun so far writing with Squiffy, but I often find myself writing waaay past midnight :P

I guess that's on me but I was wondering if there are any plans for a dark theme for our poor eyes?

I would support that, I am also in need of a different background color.
My eyes start watering after staring at the glaring white for so long.

I tried the "change background color" post instructions, but I could not make it work. (pc / prograbbing n00b)

A slightly less glaring color, pretty please?

Click on "View", then "ToggleDevTools", then adjust the Squiffy editor's CSS to your liking.