[EW] Use nx styles instead of base.css

Scan da-live and replace usage of base.css with nx styles wherever possible. New code follows this convention, but older code doesn't, and itw ould be good to bring everything to parity.

Search the da-live repository for references to base.css, then compare those areas with newer code that uses nx styles. Replace base.css usage where the existing nx styles provide equivalent coverage, and consider the work done when eligible older code follows the newer convention without changing behavior or visual parity.

Written by the indexing model from the issue text.