Container conditionals and conditional sizes

Hi,

For my personal use, I have extended the radius conditional smart use of clamp() to container queries. This is pretty straightforward swapping viewport units to cqi.

I have also extended this to conditional sizes, mainly for using them with margin-block.

This way, my sections, cards, etc. have no radius, and touch each other when full width, but get both a radius and vertical spacing when not full width.
Here is what it looks like: https://codepen.io/cbontems/pen/poGYjGK

Would this be an interesting addition to the library?

I am trying to figure if something more generic like this could avoid creating a bunch of combinations:
```css
* {
--size-if-not-full-viewport-width: clamp(0px, calc(100vi - 100%) * 1e5, var(--apply-this-size, 0px));
--size-if-not-full-container-width: clamp(0px, calc(100cqi - 100%) * 1e5, var(--apply-this-size, 0px));
--radius-if-not-full-viewport-width: clamp(0px, calc(100vi - 100%) * 1e5, var(--apply-this-radius, 0px));
--radius-if-not-full-container-width: clamp(0px, calc(100cqi - 100%) * 1e5, var(--apply-this-radius, 0px));
}

.element {
--apply-this-size: var(--size-5);
--apply-this-radius: var(--radius-3);
margin-block: var(--radius-if-not-full-viewport-width);
border-radius: var(--radius-if-not-full-viewport-width);
}
```

The issue names no source file, test, or entry point. Start by locating the library’s existing radius and size custom properties, then compare the proposed container-query behavior with the linked CodePen. Done would require a decided scope for the addition and verification that the resulting conditionals work as intended.

Written by the indexing model from the issue text.