refactor(frontend): retire legacy CSS and isolate visual artwork

vocero-frontend/README.md

@@ -131,10 +131,13 @@ Vitest handles Node 26's experimental web storage behavior internally.
 - `src/lib/`: validated backend contracts, settings, prompt context, profile
   and report presentation, Markdown sanitization, and conversation exports.
 - `config/backend-proxy.ts`: the shared HTTP/WebSocket development proxy.
-- `src/styles.css`: Tailwind integration and React-specific layout adjustments.
-- `src/styles/legacy-theme.css`: the existing visual styles, retained for
-  fidelity to both the white microphone and dark orb themes. The UI is ported
-  to React; the full design has not been rewritten as Tailwind utilities.
+- `src/styles.css`: Tailwind layer/import entry point. Preflight remains disabled.
+- `src/styles/theme.css`: semantic Tailwind tokens and server-selected theme
+  variants. Use `bg-surface`, `text-foreground`, `border-line`, and related utilities.
+- `src/components/ui.tsx`: shared buttons, icon buttons, fields and dialog controls.
+  Components own their layout, responsive utilities and interaction styling.
+- `src/styles/`: minimal element defaults and reduced motion, voice artwork,
+  sanitized Markdown, decorative surfaces and native range pseudo-elements.
 
 The current Spanish interface, local preference keys, session-only RAG,
 Markdown replies, JSON/TXT exports, optional browser wake word, TALK/TALKFIRST