# Mobile Chord System Implementation

## Overview
Implemented a chord system that allows mobile users to use Option+Arrow key combinations for word navigation:
- Option key acts as a toggle/modifier
- When Option is pressed, it activates and waits for an arrow key
- When an arrow key is pressed while Option is active, it sends the combination
- Visual feedback shows when Option modifier is active

## Implementation Details

### 1. State Management
- Added `activeModifiers` Set to track which modifiers are currently active
- Option key toggles its state in the Set rather than sending immediately

### 2. Chord Detection
- When Option is pressed, it's added to activeModifiers
- When an arrow key is pressed with Option active:
  - Clears the Option modifier
  - Sends Option (ESC) first
  - Then sends the arrow key
  - This creates the Option+Arrow combination

### 3. Visual Feedback
- Added CSS class `.modifier-key.active` with blue background
- Option button shows active state when pressed
- State clears after arrow key press or when pressing non-arrow keys

### 4. Key Mappings
- Option sends ESC (`\x1b`) - already implemented in direct-keyboard-manager.ts
- Arrow keys send their normal codes
- The combination results in ESC+arrow sequences for word navigation:
  - Option+Left = ESC+b (word backward)
  - Option+Right = ESC+f (word forward)

## Testing
Added comprehensive tests in `terminal-quick-keys.test.ts` covering:
- Toggle behavior of Option key
- Chord detection for all arrow keys
- Clearing of modifier state
- Visual update requests
- Multiple chord sequences

## Usage
1. Tap Option key (⌥) - it highlights in blue
2. Tap any arrow key - sends Option+Arrow combination
3. Option automatically deactivates after use
4. Can tap Option again to cancel without sending

This provides an intuitive way for mobile users to access word navigation without requiring a physical keyboard.