I know this does not answer your question but you can change any of the colors with uBlock filters. I can share mine but I must add the disclaimer it might make your eyes bleed. Adjust the colors based on your own preferences. I set my "topcolor" to #000000 in the UI and then the following goes into uBlock Origin "My Filters". A couple of those may not do anything any more.

    # HN Color
    news.ycombinator.com##html:style(background-color: #011 !important)
    news.ycombinator.com###hnmain:style(background-color: #011 !important)
    news.ycombinator.com##commtext:style(color: #191 !important)
    news.ycombinator.com##.toptext:style(color: #191 !important)
    news.ycombinator.com##.age:style(color: #191 !important)
    news.ycombinator.com##.c00.commtext:style(color: #191 !important)
    news.ycombinator.com##.cdd.commtext:style(color: #191 !important)
    news.ycombinator.com##.c9C.commtext:style(color: #191 !important)
    news.ycombinator.com##.c73.commtext:style(color: #191 !important)
    news.ycombinator.com##.c5a.commtext:style(color: #191 !important)
    news.ycombinator.com##.cbe.commtext:style(color: #191 !important)
    news.ycombinator.com##.c88.commtext:style(color: #191 !important)
    news.ycombinator.com##.cae.commtext:style(color: #191 !important)
    news.ycombinator.com##.cce.commtext:style(color: #191 !important)
    news.ycombinator.com##.comhead > a:style(color: #191 !important)
    news.ycombinator.com##.comhead:style(color: #191 !important)
    news.ycombinator.com##.hnuser:style(color: #191 !important)
    news.ycombinator.com##.subtext > a:link:style(color: #588 !important)
    news.ycombinator.com##.subtext > a:style(color: #191 !important)
    news.ycombinator.com##.subtext:style(color: #191 !important)
    news.ycombinator.com##.title > a:style(color: #191 !important; background-color: #011 !important)
    news.ycombinator.com##a:link:style(color: #588 !important)
    news.ycombinator.com##a:visited:style(color: #255 !important)
    news.ycombinator.com##a:hover:style(color: #191 !important; background-color: #011 !important)