It would be nice for the site to have a dark theme option
Already been added, should be able to enable it in your preferences.
Does editing preferences require a log-in?
If so, it'd be nice if it was possible to edit them without logging in, probably by just setting a cookie/DOM Storage, (like startpage.com does it) with the appropriate warning, of course.
Absolutely! Do you mind opening that as a new issue?
I think this issue can be closed for now.
Most helpful comment
Does editing preferences require a log-in?
If so, it'd be nice if it was possible to edit them without logging in, probably by just setting a cookie/DOM Storage, (like startpage.com does it) with the appropriate warning, of course.