[chrismorgan]

Courier New is a bad font that no one should choose to use. In typical font-weight terms, where Regular should be 400, it’s 200–250, because it was improperly digitised, not taking ink bleed into account. Windows put some hacks into ClearType to make it render a little less badly, but they’re not dependable these days.

(“Courier”, as provided by macOS, is fine. But Courier New is irredeemably bad.)

Concerning font-family declarations, if you’re doing something like `"Courier New", Courier, monospace`—please just write `monospace`.

(I’m not going to address the font size.)

[ricardobeat]

It renders terribly on sizes below ~14px, even on a Retina display. No anti-aliasing setting can save it.

A modern typeface like IBM Plex Mono [1] or Office Code Pro [2] that offers more weights and can still render nicely at 10px size would be a better choice, maintaining the same aesthetic.

[1] https://fonts.google.com/specimen/IBM+Plex+Mono

[2] https://open-foundry.com/fonts/office-code-pro