HN is one of the best designed websites I use daily. The information density is unmatched on the "modern" web.
The parent comment mentioned CSS changes, but I basically think the appearance should stay the same, and any accessibility improvements can probably be accomplished by changing the HTML for better screen reader compatibility, if needed.
Here’s a good starting point from Mozilla covering accessibility: https://developer.mozilla.org/en-US/docs/Learn/Tools_and_tes...
It's one of the only sites which does this today.
It's also got known accessibility issues, including for people who are blind or otherwise more visually impaired than I am.
The lead mod has acknowledged this in comments.