I'm not sure, but when I was working with UX years ago, they designed everything for a fixed width and centered it in the screen.

Kinda like how HackerNews is, it's centered and doesn't scale to my full width of the monitor.

I understand not using the full width, but unless you zoom in, it feels like I'm viewing tiny text on a smart phone in portrait mode.

You would think browsers themselves would handle the rest, if the website simply specified "center the content div with 60% width" or something like that.