Vue's scoped-CSS compiler was dropping the `:global(.dark) .settings-tabs-shell`
rules in the production build, so the tab strip kept its light-mode white
background and the inactive tab labels (text-gray-300) showed at ~1.6:1
contrast — effectively unreadable.
Hoist the three dark-mode overrides into an unscoped `<style>` block so they
survive the scoped-CSS transform.
b0c7723393