Move scattered CSS files into css/ as canonical home for all styles:
- inject.css (universal injectable, was nginx/throwback.css)
- dashboard.css (extracted from nginx/index.html inline styles)
- gitea.css, woodpecker.css, marimo.css (moved from service dirs)
- throwback.css (reference palette, single source of truth)
Rewire compose.yml volume mounts to source from css/.
245ef1c3b6
