# Project Guidelines

## Code Style
- Keep components as functional React components and use hooks-based state.
- Follow existing naming and structure in `src/screens` and `src/components`:
  - Screen files: `*Screen.js`
  - Shared UI pieces: `src/components/*.js`
- Keep styling centralized in `src/styles.js` via `createStyles()` and use theme-driven inline color overrides in screens/components.
- Reuse `getTheme(darkMode, pinkMode)` from `src/theme.js` for color values; do not hardcode alternate palettes in individual screens.

## Architecture
- Root orchestration lives in `App.js`:
  - App-level state includes current screen, focus mode, theme toggles, and timer/countdown state.
  - Screen switching is controlled by the `screen` state (`home`, `timeuntil`, `timer`).
- Screen responsibilities:
  - `HomeScreen`: mode selection and top controls.
  - `TimeUntilScreen`: target clock-time countdown flow.
  - `TimerScreen`: duration countdown flow.
  - `FocusScreen`: minimal fullscreen countdown UI.
- Shared presentational components:
  - `TopControls`: dark/pink/fullscreen/focus controls.
  - `CountdownRow`: reusable HH:MM:SS display.

## Build And Run
- Install dependencies: `npm install`
- Start dev server: `npm start`
- Run on Android: `npm run android`
- Run on iOS: `npm run ios`
- Run on web: `npm run web`
- EAS builds use `eas.json` profiles (`development`, `preview`, `production`).

## Conventions
- Keep timer/countdown behavior in `App.js` unless intentionally refactoring architecture.
- Preserve current time behavior:
  - `now` updates every second with `setInterval`.
  - Time-until target is based on local device time and rolls to next day when target time has passed.
- Maintain platform guards:
  - Web-only fullscreen uses `document.fullscreenElement` APIs.
  - Android hardware back behavior is handled in `App.js` and should keep focus/screen fallback behavior.
- For countdown display, continue using `CountdownRow` and 2-digit padded units for consistency.

## Pitfalls
- This project has no test scripts configured; do not claim tests were run unless you add and run them.
- Be careful with web-only globals (`document`) and keep `Platform.OS` guards.
- Avoid introducing timezone assumptions without explicit product requirements; current logic is local-time based.