Is Webflow force custom code REM's to PX?

I have find that custom CSS size in REM is automatically recalculated to PX at least it shows px values in previewer. Is there any way I can set Webflow to use rems without recalculating rems back to px? Reason for this that I have build App in Svelte that generates custom Spacing system and I would like to preserve rem units.

CleanShot 2022-06-22 at 23.50.02

there is also another issue that WF doesn’t recognise - before prefix for negative margins. Thats minor issue as I can replace - with any letter but…