A few remarks (not all that I could make, but I should sleep).
System UI: risky, it’s a trap, there’s basically no legitimate scenario for these semantics on the public web. See https://github.com/w3c/csswg-drafts/issues/3658 (skim through a bit, I’ve got a comment near the end too).
Monospace Slab Serif:every one of the fonts named here is a bad font:
(b) Courier New is unreasonably thin due to bad digitisation techniques which used to be worked around by hinting and ClearType special-casing, but it’s common for neither of those to work to make it tolerable any more. Its 400 weight is more like a 250 (if even that), and painful to read in many common configurations. Never use it.
(c) Cutive Mono apparently copied Courier New’s known-awful thinness!? What were they thinking?
Monospace Code: seriously, just go `monospace, monospace` these days. Firefox 98 on Windows was the last browser where this wasn’t at the very least perfectly adequate. (The doubling is to work around the stupid probably-13px font size misfeature that I’d like to try to convince browser makers to ditch, but haven’t tried yet.)
> Emoji Support
Does adding these fonts to the end of the stack actually achieve anything useful? I don’t recall these being necessary or useful. (I vaguely recall some sort of priority issue related to text/graphical representations, but that was quite a few years back and I’d expect it to have been dealt with now, though it’s possible some U+FE0F might be needed if you omit this?—though frankly that’d be needed anyway for universal support. Anyway, I’d like concrete explanation of what this stuff does, if anything.)
> Anti-Aliasing
If I recall correctly, these tweaks are largely Apple-specific, grossly misleading in name, highly controversial, and probably a waste of time. I invite correction or further education, because I haven’t thought about them for maybe a decade and don’t use a platform where they do anything.
—⁂—
This is much better-thought out than most sets of suggestions, but I’d honestly still suggest dropping nuance in most cases, and just using `serif`, `sans-serif` or `monospace, monospace`. But if you want a certain general sort of character, this is pretty good stuff. I’ve definitely done `font-family: Georgia, serif` where I wanted to express a preference for a wider sort of serif, and I’d do it again¹.
—⁂—
¹ Even if I personally will get my own chosen serif font, since I’ve unticked Firefox’s Settings → Fonts → Advanced → Allow pages to choose their own fonts, instead of your selections above. Try it yourself, you might be pleasantly surprised at how much the consistency improves the web, like I was. You might also develop a still-deeper hatred of non-zero letter-spacing on body text, which is absurdly common for something that has absolutely no legitimate use case in English text.
> System UI: risky, it’s a trap, there’s basically no legitimate scenario for these semantics on the public web.
How else would you style things with the system's UI font? User interfaces on the web can be designed to fit in the native system UI. It's a legitimate and useful thing to do.
I don't see how you can make a meaningful distinction between what's "online" or "on the public web" or not. A lot of web apps can run both online and offline, installed or uninstalled. In all cases it uses the same web technology.
Just because some legacy system makes a bad choice, doesn't mean everyone can't have nice things. I mean, did Windows seriously make all their UI use a single font? Do they just assume all the UI on Windows would be monolingual...?
I mean, it's standard practice to use a Latin font and fallback to other fonts for complex scripts such as CJK, because it's universally acknowledged that the Latin glyphs in these fonts are terrible and unfit even for the purpose of using it with the CJK characters.
Instead of discouraging or even removing it, how about actually encouraging people to use `system-ui` to force Microsoft and other companies to fix their systems?
Reading the thread it's clear cooler heads have already prevailed. The recommendation from the remove system-ui crowd was that there would be no way to access the system font outside of sans-serif. Why? Because some people have been using system-ui wrong.
If wrong use were cause enough to remove things from the web, we'd have lost tables in 1997.
—⁂—
A few remarks (not all that I could make, but I should sleep).
System UI: risky, it’s a trap, there’s basically no legitimate scenario for these semantics on the public web. See https://github.com/w3c/csswg-drafts/issues/3658 (skim through a bit, I’ve got a comment near the end too).
Monospace Slab Serif: every one of the fonts named here is a bad font:
(a) Nimbus Mono PS mangles things like the two-column `fi`, ligating them to a single-column `fi`. See https://github.com/ArtifexSoftware/urw-base35-fonts/issues/3....
(b) Courier New is unreasonably thin due to bad digitisation techniques which used to be worked around by hinting and ClearType special-casing, but it’s common for neither of those to work to make it tolerable any more. Its 400 weight is more like a 250 (if even that), and painful to read in many common configurations. Never use it.
(c) Cutive Mono apparently copied Courier New’s known-awful thinness!? What were they thinking?
Monospace Code: seriously, just go `monospace, monospace` these days. Firefox 98 on Windows was the last browser where this wasn’t at the very least perfectly adequate. (The doubling is to work around the stupid probably-13px font size misfeature that I’d like to try to convince browser makers to ditch, but haven’t tried yet.)
> Emoji Support
Does adding these fonts to the end of the stack actually achieve anything useful? I don’t recall these being necessary or useful. (I vaguely recall some sort of priority issue related to text/graphical representations, but that was quite a few years back and I’d expect it to have been dealt with now, though it’s possible some U+FE0F might be needed if you omit this?—though frankly that’d be needed anyway for universal support. Anyway, I’d like concrete explanation of what this stuff does, if anything.)
> Anti-Aliasing
If I recall correctly, these tweaks are largely Apple-specific, grossly misleading in name, highly controversial, and probably a waste of time. I invite correction or further education, because I haven’t thought about them for maybe a decade and don’t use a platform where they do anything.
—⁂—
This is much better-thought out than most sets of suggestions, but I’d honestly still suggest dropping nuance in most cases, and just using `serif`, `sans-serif` or `monospace, monospace`. But if you want a certain general sort of character, this is pretty good stuff. I’ve definitely done `font-family: Georgia, serif` where I wanted to express a preference for a wider sort of serif, and I’d do it again¹.
—⁂—
¹ Even if I personally will get my own chosen serif font, since I’ve unticked Firefox’s Settings → Fonts → Advanced → Allow pages to choose their own fonts, instead of your selections above. Try it yourself, you might be pleasantly surprised at how much the consistency improves the web, like I was. You might also develop a still-deeper hatred of non-zero letter-spacing on body text, which is absurdly common for something that has absolutely no legitimate use case in English text.