[dang]

That's because HN's software now rewrites links to the canonical URL, and https://elis.nu/blog/2021/09/dynamic-css-color-themes-with-s... includes

  <link href="https://elis.nu/" rel="canonical">

I've put your intended URL back up there but you might want to fix that in your HTML :)

[etu]

Oh, I guess that got there by mistake when I was migrating the page years ago. I've changed it in my template files. :)