[p_l]

Unfortunately, while making a site, I can't query for "does the user set special preferences" in CSS.

I use somewhat similar formula in one project to create a common baseline font size that 1) does not break with viewport size changes 2) remain legible for baseline user 3) gives good base value to scale UI elements by rem/em units.

Of course it's also a project where the user does not have a chance to mess with font size anyway for the main user, but I'd reuse the formula elsewhere.

Wish I could query the browser if the user has specific preferences, just like with "Dark mode"

[persnickety]

You don't query for it; you don't override. Either the setting is custom and desired, or it's default and it hasn't been adjusted because it's fine.

[p_l]

My personal experience is that the default is usually wrong, especially when I move between different displays. I end manually zooming in/zooming out a lot.

Meanwhile using the default size + CSS keyword size modifiers (large/x-large etc.) ended up on breaking on the project I mentioned, especially after for all practical purposes we had to deal with the fact that claims of single display size & resolution to target weren't actually delivered, and when client also asked about possibly opening the interface from portable devices.

[account42]

> My personal experience is that the default is usually wrong, especially when I move between different displays. I end manually zooming in/zooming out a lot.

Then fix your setup. Campaing for better browser defaults. Do whatever it takes, but don't add hacks with hardcoded (=faulty) assumptions to your websites.

[persnickety]

Sadly, I agree that browsers have forgotten what defaults are for. Instead of prvoiding something useable for the user, default CSS has turned into a nearly completely abstract set of values of relevance only to developers.

But that situation should be fixed on the side of the Web browsers, not every website's author.

[mcherm]

OR, the setting is default and it hasn't been adjusted because the user doesn't have the faintest idea how to adjust font sizes.

Which I suspect is the case for the majority of end users.

[account42]

The responsibility for making sure the default is reasonable for those users is the browser vendor, NOT each individual website.

[account42]

> Wish I could query the browser if the user has specific preferences, just like with "Dark mode"

You can't query that with dark mode since there is no "no-preference" in the spec and the "preference" that browsers expose normally has not been influenced by the user in anyway. You should still respect the indicated dark mode preference because the user can influence it to set their preference for all sites. Same with the font size.