Wrap fluid clamp() middle terms in calc() for Ruby…

Details

The github-pages / jekyll-sass-converter (Ruby Sass 3.7.4) evaluates
arithmetic inside clamp() and rejects mixed units, failing the Pages
build on `clamp(1.8rem, 1.4rem + 1.1vw, 2.3rem)`. dart-sass (local
css:check) passes it through, so it read green locally. Wrapping the
middle term in calc() compiles clean under both. No visual change.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YB1axhX3kbHCFJbX7LhfH8

Files changed (2)