[pwg]

> When is Hacker News going to have an option for a dark mode.

Browsers have the alternate name "user agents" for a reason, they are ultimately intended to be working for you, the user.

Therefore, simply adjust your "user agent" (browser) to give you a dark mode, and you will have a dark mode, without needing or waiting for HN to change anything.

The comment from @LinuxBender here shows you one way to do so using uBlock Origin.