Hacker News Reader

The ebook editions are very good for this. Most of the e-reader software provides all the amenities (bookmarks, highlighting, notes, control of margins, etc).

Firefox's reader mode works amazingly for these situations.

A while back I attempted to extract the FF reader code to make it a front end to various non-web clients (email with pine key bindings etc)

I got it to a prototype level but then shelved it after having difficulty getting good results with various test datasets. Probably would make a fantastic ereader though

Lines aren't too long. They look great on all my devices.

Use ⌘ + + until you get the line length you like.