In reply to Justin Tadlock.

I certainly can't argue that the classes in that demo are rough. Maybe a t-shirt scale is the answer after all. I'd love to hear other ideas and see what other systems do. That's an area where I've done some research but not a ton, and it's hard to find systems that are exactly like what I'm proposing (which is only a starting point in itself).

You might notice that I start skipping numbers after a bit because I find those “in-between” points less and less useful as the scale goes up.

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At the other end of all this, even if we all agree to some standard naming system, there is potential for monumental differences between implementations. For example, imagine my theme defining --wp--preset--margin-1 to 0.25rem and another theme defining that as 2rem with an ever-increasing scale. It could get out of hand when switching themes.

I think having a contiguous scale with no gaps is key. There shouldn't be any implied connection between the position on the scale and the actual value. I actually have no problem with your example there so long as margin-1 is consistently understood to occupy the same relative position on a scale.

A final thought I have that's relevant here though (and gets to the questions around standardizing) is that I think the wider the scales and the greater the number of standardized values, the more disagreement there will be between themes, the "farther from center" things get. If a primary color is maintained from theme to theme, that's super valuable. If a quaternary color is maintained, that's probably less valuable since many themes may not even have one colors further down in a brand guide are often more specific and unique in how their use is intended. think the same goes for transferring a 5-point scale vs a 13-point scale. I think as long as there's a system that lets theme's use their 13-point spacing scale in their CSS but maybe only provides 5 or 7 options through the UI, that seems both like a likelier path to success and an easier set of things to agree on.