Live and Fleet primary nav tabs share the same accent color (–dsc-blue)

Fixed, and worse than first reported: .dsc-tab–live.active/.dsc-tab–fleet.active both used var(–dsc-blue) (equal-specificity collision), but a later .dsc-tab.active rule (dsc.css) was ALSO overriding every section’s color to white regardless — the whole color-by-section system was dead, not just Live/Fleet. Rescoped the section rules under .dsc-primary-tabs to win on specificity; Fleet reassigned to purple (freed up when Tune was removed). See PR weddas/DSC-HUB#178. Needs a visual check in a browser — CSS specificity fix verified by reading, not rendered.