Problem/Motivation
#3084843: Update browserslist browsers updated the browserslist browsers to match with the updated Drupal browser support policy #2390621: [policy, no patch] Update Drupal's browser support policy. As part of the issue we ensured that there were no changes to production JavaScript. However, browserlist is also used by our CSS tooling and this leads into some changes in the production code.
Proposed resolution
Re-generate production CSS files.