Please consider the possibility of per-*site* fonts and not just per-*person*.  On Stack Exchange, Mi Yodeya ran into a problem because the default font (post-redesign) had really terrible support for Hebrew, which we cared about.  I think the Mathjax-using sites also had some problems with the default font, though I don't recall the details.

This concern has two implications:

- We might need to customize a font at the site level.

- A per-user font setting *does not solve the problem*, because different sites might have different needs.  (I chose a different font here because I found the original one hard to read; if that original were to be the one that supported Hebrew, for instance, I'd have to choose between the Hebrew on one site and legibility on all sites.  That would be unfortunate.)

It's a reasonable idea, but the choices should be very limited.

Having multiple typefaces might make support more time-consuming, since issues might arise with one choice but not another.

For example, messages with mixed text and `code` inline formatting, sometimes appear with very small scrollbars in chat. Things like this might depend in the future on which typeface was chosen, along with the already myriad possibilities of OS, device, browser...and so on.

I quite like the current typeface, but agree with @dezso that a sans-serif option would be welcome.

Yes, absolutely. A few carefully selected options by default and a "write in" option for those who know what they want and have it on their computer would be great, possibly with the write in being a CSS field so Google Fonts or other providers could be sourced in an `@import`.

Contrary to a previous answer, having a limited selection is not benefit to support. Only having a fixed single selection would be a real benefit (same for everybody). As _soon as_ you get into allowing different fonts you pretty much open up Pandora's box — but then again allowing flexible width layouts does that too.

The sooner this becomes an option the less "debt" will be built up by posts that assume they know exactly how they will be presented. If a Markdown is enough to represent content, then a choice of fonts on the UI site should be included just to prove that the content isn't dependent on the font.

*Note SE has avoided font options and even flexible width layouts over the years because they are very hard to add into the mix later (you break all the posts that assumed a fixed width and hacked their content to match).*

Would it work to allow the user to add their own custom CSS? This would solve the problem for those that care enough to know or work out how to change look and feel, while letting devs focus on other features.