If you use uBlock Origin, here's how to add automatic dark mode, based on your browser settings (modify "90%" slightly to adjust the contrast):

  ! dark mode
  news.ycombinator.com##html:matches-media((prefers-color-scheme: dark)):style(filter: invert(90%) hue-rotate(180deg))

Funny enough, I use HN as a gentler flashlight when I enter my bedroom after my spouse is asleep as it’s one of the few sites/apps that doesn’t have a dark mode.

I use the “HN Dark Mode” add-on set to “auto” so it switches with my OS preferences.

Both on iPhone and Mac.

Just use dark reader, it works extremely well here.