[ossopite]

This sounds plausible but I'm not sure it's quite accurate, because in my experience, zooming in also affects the size of things that use px units in CSS.

[no_way]

Yeah, zoom changes page scale factor you can see it's computed value window.devicePixelRatio and that in return changes everything. Font-size can be also be changed independently of zoom inside browser settings.

https://developer.mozilla.org/en-US/docs/Web/API/Window/devi...

[mark-r]

px units are not actual pixels, they're a synthetic approximation. I don't remember the exact formula but I'm sure it's affected by font scaling the same as everything else.

[wizzwizz4]

They're defined in terms of inches. I don't remember the fraction of an inch that a CSS pixel is.

[mark-r]

I believe it's 1/96, while a point is 1/72.