1. People who never adjust font size.

2. People who regularly adjust font size as needed.

The first group is helped by a reasonable responsive font size. The second group isn't hindered by it.

Is there really a significant group of people who carefully set their preset font size, but then do not adjust it as needed when they visit a page? It seems unlikely to me. Even if all webpages used your defaults, there’s still no one-size-fits-all preset to pick, since typeface, weight, layout, leading, colors and many other things also impact readability. The tool to take control of all of that is reader mode, which is a great option when a website has screwed up its typography.

Of course CSS actually does. I've found using font size keyword and rem units can make a UI that scales with user preferences quite possible. Not _easy_ of course, but possible.

As it seems from your post that you may not be extremely familiar with CSS, here is a ruleset that will do something close to what you wish. Font is set to 26px, not 14. You can easily change that.

Make it valid for "Everything" and it will be valid for everything but those sites that are extremely convoluted.

    *, html, body, section, article, div, span, p, i, b, strong {
        font-family: "Libre Sans" arial, helvetica, sans, sans-serif !important;
        font-size: 26px !important;
        font-weight: bold;
        line-height: 1.5em !important;
        background-color: white;
        color: black;
    }
    pre, code {
        font-family: "Libre Mono", Courier, monotype !important;
    }
   a {
        text-decoration: underline;
   }

The Dark Reader addon for Firefox is somewhat poorly named, it seems to be a pretty solid overall website customization tool. It can, for example:

* force websites into light mode

* change backgrounds to plain white and text to plain black

* apply tints in general

* force font line width changes.

Might be worth a glance. I have pretty good vision but I just use it because the way the internet is supposed to work is: send me text, I’ll render it however I want. This lets me ignore more meddling by designers.

At the browser level I've found myself wanting to reorganize layout quite a bit, and am starting to think about templating from a user perspective beyond light/dark theme. What assumptions am I making about intent in my work? How can I provide flexibility and when should I step back and just link a csv dump?

I think my ideal modern browser looks more like a crawler. Display of info loosely coupled to site content. All of the scripts I'd actually want to run pulled down on my side from public repos.

I wonder if there are custom CSS chrome extensions that allow you to apply a font to all sites not just one.

  :root {
    font-size: 1rem;
  }

Everybody please clamp!

The main container’s width on their website also doesn’t scale infinitely, so on a very wide screen you’d have a lot of blank space on both sides.

That being said, it might still be reasonable to set a break point (or use CSS clamps) and prevent further font-size growth beyond a certain point.

It's because the first phone browsers had an insane default, and the standards body decided the insanity should be kept for backwards compatibility.

Having a viewport meta turns the insanity off, but only if you set the content area.

The idea behind it was that the browser default font size was 16px, so if you set the root font size for your document to 62.5%, then 1em = 10px, and designers who really, really wanted to work with pixels could use ems and pretend they were using pixels without doing complicated maths every time they wanted to set the size of something – they just needed to divide or multiply by ten.

The reason for not just using pixels was partly because it was drummed into everybody’s heads at the time that ems were better than pixels (which, in context, they were, but not when you pretend they are pixels), and partly because Internet Explorer at the time was unable to resize text set in pixels when you increased the text size, which was an accessibility failure.

The problem with this idea is that pixels and ems are fundamentally different types of unit. You can’t make them equivalent using any kind of calculation in CSS. Pixels are objective, whereas ems are based on user preferences. The browser might default to 16px font size, but users can pick something else. So if somebody had poor vision and increased their default font size; or if they had a small laptop screen and decreased their default font size, 1em * 62.5% != 10px, everything the designer set in ems was a different size than they intended, and a lot of their page layouts disintegrated into an unholy mess.

You can’t convert between ems and pixels in CSS. Any calculation like this is fundamentally broken from the start. Nobody should have ever used the 62.5% hack.

I ask just because not very many people seem to clamp yet, so looking for experiences.