Confidence Score: 5/5

Safe to merge. The change is minimal and targeted, mirrors the pattern used in the main compilation path, and is backed by an inline snapshot test.

The diff is a single extra line adding substituteAtVariant to the addBase pipeline, identical to how it is used in index.ts and design-system.ts. The return value is correctly OR'd into featuresRef.current. The new test validates both a media-query breakpoint variant and a compound/comma-separated selector variant, covering the main code paths in substituteAtVariant.

No files require special attention.

_{Reviews (1): Last reviewed commit: "update changelog" | Re-trigger Greptile}

No actionable comments were generated in the recent review. 🎉

Walkthrough

This PR adds support for using @variant directives inside the addBase() plugin API. The implementation imports the substituteAtVariant helper function and applies it within the base AST processing flow in addBase(). A comprehensive test verifies that nested @variant directives are correctly transformed into equivalent media queries and selector rules, while the changelog documents the new capability.

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