I have encountered an issue with Lightning CSS where LogicalProperties are not converted when a CSS variable is used within a calc() expression. In the provided minimal reproducible example, the conversion for inset: calc(var(--test)) is skipped, even though the result of the calc() (with var(--test) defined as a concrete value) should be processed and converted accordingly.

Minimal Reproducible Example:

Playground Example

Steps to Reproduce:

1. Open the above playground link.
2. Observe the CSS source, which includes:

.foo {
  --test: 10px;
  inset: 0;
  inset: 10px;
  inset: calc(var(--test));
}

3. Process the CSS using Lightning CSS with a target configuration that should trigger conversion of LogicalProperties.
4. Notice that while the plain inset values are converted, the calc(var(--test)) is not converted.

Expected Behavior:

Even when using calc(var(--test)), since --test is defined with a concrete value, the result of the calc() should be a computable value. Therefore, it should be eligible for conversion to its corresponding physical properties (e.g., converting logical properties to physical ones based on target browser support).

Actual Behavior:

The conversion step for inset: calc(var(--test)) appears to be skipped, and the property remains unchanged.

Additional Context:

Since calc() expressions with CSS variables should yield a definite value, I believe that the current behavior might be an unintended bug in the conversion logic of Lightning CSS. Any guidance or fix on this issue would be highly appreciated.