- Replace 28-line backend/internal/web/ui/base.css stub with full go-backend token vocabulary (223 lines, --color-brand-primary: #804eec) - Create backend/internal/web/ui/auth.css with auth-provider button styles extracted from button.css Phase 8 block - Update backend/tailwind.input.css to import auth.css after base.css
- tokens.go: semantic token constants - variants.go: Size/ButtonVariant/ButtonTone/BadgeVariant enums + Normalized* - helpers.go: mergeAttrs for templ.Attributes - base.css: resets, :focus-visible ring (no nesting)