Why icon size in json and font size in css?

[MartenBE]

As a beginner I am confused why icon-size must be specified in the json file, but all other sizes like font-size or paddings must be specified in the css file. This makes it hard to be consistent. Why do we need to specify sizes in 2 different files?

[msmafra]

The font-size and icon-size options are for different things: icon-size is for the tray and taskbar modules icons, desktop icons from programs (PNGs, SVGs etc) not for symbols fonts from fonts.
icon-size if for things like Firefox or Steam client icon to be shown inside the Task bar or Tray.

[MartenBE]

But both are pixel values, I think? Is there a way to set them once using a variable so when changed we don't have to change them everywhere in both files manually?

Why aren't the sizes a part of the css (which seems more logically to me)

[msmafra]

But both are pixel values, I think?
In the end, yes they are pixel values. but fonts you set with our CSS which can use different units causing different behaviors.

Is there a way to set them once using a variable so when changed we don't have to change them everywhere in both files manually?
As far as I know there isn't a native way to set a variable. I can only see in current version, the use of a script to do so. I think, dunno and not sure, just in shells like Quickshell, AGS etc you have that flexibility. BUt I found them much more complex to have working.

Why aren't the sizes a part of the css (which seems more logically to me)
More logically for me too. But is limited to the set of CSS and custom CSS that GTK3 accepts, which I not complete familiar with.