This surprisingly works well. One thing, the background of body is still white for me on desktop this is what I have (combine with someone else who commented about the brightness):

    @media (prefers-color-scheme: dark) {
      body {
          background: #222222;
          filter:invert(1) hue-rotate(180deg) brightness(0.9)
      }
    }

Edit, also works on hn.algolia.com

> the background of body is still white for me

Had the same problem, changed "body" to "html", added background: #fff, now it works.

I turned it into a bookmarklet to make it easy to use on any website:

javascript:styles='html {filter: invert(1) hue-rotate(180deg) brightness(.9); background-color: #fff; }'; newSS = document.createElement('style'); newSS.type = 'text/css'; newSS.innerHTML = styles; document.documentElement.getElementsByTagName('head')[0].appendChild(newSS);void(0);

Use stylus to automatically inject it.

Unfortunately the colors are a bit too bright for the dark page.

append brightness(.9) to the end of the filter

This is the hacker-est option, I love it. So simple