I use the following in ublock origin to change the look of HN. You can definitely restyle the site to your liking!

    news.ycombinator.com##html:style(filter:invert(95%) hue-rotate(200deg); background: white)

Edited to add: screenshots here: https://gist.github.com/aclarknexient/c39c83f2f97c3c6b1c307c...