[css-values] Can we remove the limit for @property initial-value being computationally independent?

This came up in the discussion of https://github.com/w3c/csswg-drafts/issues/12735

Authors have used custom properties for a long time to establish design systems. The general approach is to define things on the root. These values may or may not be computationally independent, and the authors is not considering that distinction specifically. These are reasonable context-dependent props from a design system:

html {
  --accent-color: light-dark(deepPink, hotPink);
  --complementary-color: oklch(from var(--accent-color) l c calc(h + 180));
  --gap: round(2cqi, 0.25lh);
  --xx-large: 2.5em;
}

Now there are various reasons that an author might want to move any one of those into @property - to support animating, or enforce a type, or turn off inheritance, etc. And @property allows us to set what seems like a global variable fallback in the initial-value. From an authoring perspective, any and all of these seem like reasonable global fallbacks for my custom property. But none of them are allowed as initial-value settings. And the 'computationally independent' restriction is not a concept that exists anywhere else when authoring. It's surprising when you try to move custom property 'defaults' from the root to @property and you run into a totally unfamiliar restriction.

/cc @tabatkins who asked me to open the issue

Start by reading the linked CSSWG issue 12735 and this discussion about the @property initial-value restriction. Trace the specification text defining computational independence and determine whether the proposal has consensus; done means an agreed standards change or a documented resolution.