Why px for spacing and rems for others

[kvpasupuleti]

I have gone through various design systems for deriving the units for our design system.

Why is tailwind using px for paddings and margins and rems for others including other spacings and sizing?

Any base for this decision here?

[adamwathan]

Hey! We use rem for padding and margin, not pixels.

[kvpasupuleti]

@adamwathan
But, according to these docs, padding and margin are mentioned in px

https://tailwindcss.com/docs/padding
https://tailwindcss.com/docs/margin

[cannap]

yes but only the 0 values

[yevgeniy-belov]

Im wondering why using rems for spacing - doesn't it make the custom font size feature of the browsers less useful?
If a user wants to make everything bigger she can Zoom In but if she wants to make only the texts bigger, without consuming even more real estate, she should be able to do so. WDYT?