[verified] feat: add timer customization and themes

README.md

@@ -12,6 +12,17 @@ A browser-based Pomodoro timer and clock built with React, TypeScript, and Vite.
 - Accurate countdown after background-tab throttling
 - Sound notification when a segment ends
 
+## Stage 2
+
+- Custom focus, short-break, and long-break durations
+- Six built-in backgrounds: three gradients and three local illustrated scenes
+- Adjustable background overlay and text color
+- Four clock and timer font styles
+- Live customization preview with one-click reset
+- Automatic settings persistence in IndexedDB
+
+All preferences stay in the browser. No account or backend is required.
+
 ## Development
 
 ```bash
@@ -27,6 +38,14 @@ npm run lint
 npm run build
 ```
 
+## Architecture
+
+- React and TypeScript for the interface and timer state
+- Absolute timestamps for accurate countdowns after tab throttling
+- Native IndexedDB for persistent browser settings
+- CSS custom properties for live themes, fonts, colors, and overlays
+- Vitest and Testing Library for model, persistence, and interface tests
+
 ## License
 
 [MIT](LICENSE)