An inverted purge that scans for classes being used and merges them

[Soviut]

The purge feature is what makes Tailwind possible in many respects. The combined matrix of utility glasses that are generated produce extremely large CSS files and purging reduces that to only the classes you're using.

Rather than this subtractive approach, I propose an additive approach; Scan the source code but only merge classes that are found.

This would make it unnecessary to configure variants (like hover states on box shadows) because the scanner could simply detect the use of a variant and included the related classes in the merge.

This could potentially improve build speeds PostCSS webpack builds #2544