Some elements are not visible anymore on small screens

Reproduction steps

1. Visit a Live Data on a small screen (e.g., width 480px)
2. observe the filters

Expected

The filters are stacked at the top of the LD

Actual

The filters are missing

Analysis

Media queries cannot rely on CSS variables. That was overlooked when migrating LD stylesheet out of less when upgrading to Vue 3 (XWIKI-23024)