# Product Requirements Document: Simple Todo Application

## Overview
Create a basic todo application with essential CRUD operations and local storage persistence.

## Core Features

### 1. Todo Management
- **Add New Todos**: Input field with submit button
- **Edit Todos**: Click to edit todo text inline
- **Delete Todos**: Delete button to remove todos
- **Toggle Completion**: Checkbox to mark complete/incomplete

### 2. Basic Organization
- **Filtering**: Show All, Active, Completed views
- **Search**: Simple text search through todos

### 3. Data Persistence
- **Local Storage**: Save todos to browser localStorage
- **Auto-save**: Changes saved automatically

### 4. User Experience
- **Responsive Design**: Works on desktop and mobile
- **Clean Interface**: Simple, intuitive design

## Technical Requirements

### Frontend Architecture
- **React 18** with modern hooks
- **TypeScript** for better development experience
- **CSS Modules** or styled-components for styling

### Data Model
```typescript
interface Todo {
  id: string;
  text: string;
  completed: boolean;
  createdAt: Date;
}

interface AppState {
  todos: Todo[];
  filter: 'all' | 'active' | 'completed';
  searchQuery: string;
}
```

### Development Tools
- **Vite** for fast development
- **ESLint + Prettier** for code quality
- **Vitest** for testing

## User Stories

1. **As a user**, I want to add new todos so I can track my tasks
2. **As a user**, I want to edit todos so I can update task details
3. **As a user**, I want to delete todos so I can remove completed tasks
4. **As a user**, I want to mark todos complete so I can track progress
5. **As a user**, I want to filter todos so I can focus on specific items
6. **As a user**, I want to search todos so I can find specific tasks

## Success Criteria

- ✅ All CRUD operations work correctly
- ✅ Data persists across browser sessions
- ✅ Filtering and search work properly
- ✅ Clean, responsive interface
- ✅ Basic test coverage

## Implementation Plan

### Phase 1: Core Features
- Basic todo CRUD operations
- Local storage persistence
- Simple list display

### Phase 2: Organization
- Filtering system (all/active/completed)
- Search functionality
- Improved styling

This simple todo application demonstrates modern React development practices with essential functionality.