My experience, for decades, has been that ems / rems are almost always preferable for scaling anything that's relative to text: body width, margins, padding, etc.
It's also possible to scale text itself to the reader's own preference if any by setting the body font size to "normal". Assuming the reader has set that value in their browser, they get what they expect, and for the 99.99966% percent of people who go with their browser's shitty default, well, they can zoom the page as needed.
(Most people don't change defaults, which is one key reason to use sane ones in products and projects.)
Sites which use px or pt (o hai HN) for scaling of text or fonts absolutely uniformly fail to please for me.
(See my HN madhackery CSS mods links in my profile here, that's what I'm looking at as I type this here. On my principle e-ink browser, those aren't available, and I'm constantly fiddling with both zoom and contrast settings to make HN usable.)
Making pixel-based styling even more janky by not being actual pixels any more seems ... misguided.
It's also possible to scale text itself to the reader's own preference if any by setting the body font size to "normal". Assuming the reader has set that value in their browser, they get what they expect, and for the 99.99966% percent of people who go with their browser's shitty default, well, they can zoom the page as needed.
(Most people don't change defaults, which is one key reason to use sane ones in products and projects.)
Sites which use px or pt (o hai HN) for scaling of text or fonts absolutely uniformly fail to please for me.
(See my HN madhackery CSS mods links in my profile here, that's what I'm looking at as I type this here. On my principle e-ink browser, those aren't available, and I'm constantly fiddling with both zoom and contrast settings to make HN usable.)
Making pixel-based styling even more janky by not being actual pixels any more seems ... misguided.