Other commenters have mentioned BeeLine Reader as a way to achieve the same visual tracking benefit that you aim to achieve with right-alignment.

I'm the founder of BeeLine Reader and wanted to mention that we have a JS widget and I'd be happy to provide it to any HNer for free. Over the years, several HNers have put our tech on their websites (examples here [1]), and we've even worked with a YC company (Insight Browser [2]).

Feel free to contact me (info in profile) if you're interested in trying out BeeLine Reader on your website.

1: https://thegradient.pub/has-ai-found-a-new-foundation/ https://wildcardpeople.com/what-is-a-wildcard-person https://jaack.me/cleanmymac-x/

2: https://insightbrowser.com/collections/reading