react-native-sop-docs/04-design-integration/design-system.md

# Design System Setup

## Theme Configuration

**Install design dependencies:**
```bash
yarn add react-native-vector-icons react-native-svg
yarn add -D @types/react-native-vector-icons
```

**Theme Configuration:**
```typescript
// src/config/theme.ts
export const Colors = {
  primary: '#007AFF',
  secondary: '#5856D6',
  success: '#34C759',
  warning: '#FF9500',
  error: '#FF3B30',
  background: '#F2F2F7',
  surface: '#FFFFFF',
  text: {
    primary: '#000000',
    secondary: '#6D6D80',
    disabled: '#C7C7CC',
  },
  border: '#E5E5E7',
};

export const Typography = {
  h1: {
    fontSize: 32,
    fontWeight: '700' as const,
    lineHeight: 38,
  },
  h2: {
    fontSize: 24,
    fontWeight: '600' as const,
    lineHeight: 30,
  },
  body: {
    fontSize: 16,
    fontWeight: '400' as const,
    lineHeight: 22,
  },
  caption: {
    fontSize: 12,
    fontWeight: '400' as const,
    lineHeight: 16,
  },
};

export const Spacing = {
  xs: 4,
  sm: 8,
  md: 16,
  lg: 24,
  xl: 32,
};
```

## Design Tokens

Create a comprehensive design token system:

```typescript
// src/config/designTokens.ts
export const DesignTokens = {
  colors: {
    // Primary palette
    primary: {
      50: '#E3F2FD',
      100: '#BBDEFB',
      500: '#2196F3',
      700: '#1976D2',
      900: '#0D47A1',
    },
    // Semantic colors
    semantic: {
      success: '#4CAF50',
      warning: '#FF9800',
      error: '#F44336',
      info: '#2196F3',
    },
    // Neutral colors
    neutral: {
      white: '#FFFFFF',
      gray50: '#FAFAFA',
      gray100: '#F5F5F5',
      gray200: '#EEEEEE',
      gray300: '#E0E0E0',
      gray400: '#BDBDBD',
      gray500: '#9E9E9E',
      gray600: '#757575',
      gray700: '#616161',
      gray800: '#424242',
      gray900: '#212121',
      black: '#000000',
    },
  },
  
  typography: {
    fontFamily: {
      regular: 'Montserrat-Regular',
      medium: 'Montserrat-Medium',
      semiBold: 'Montserrat-SemiBold',
      bold: 'Montserrat-Bold',
    },
    fontSize: {
      xs: 12,
      sm: 14,
      base: 16,
      lg: 18,
      xl: 20,
      '2xl': 24,
      '3xl': 30,
      '4xl': 36,
    },
    lineHeight: {
      tight: 1.25,
      normal: 1.5,
      relaxed: 1.75,
    },
  },
  
  spacing: {
    0: 0,
    1: 4,
    2: 8,
    3: 12,
    4: 16,
    5: 20,
    6: 24,
    8: 32,
    10: 40,
    12: 48,
    16: 64,
    20: 80,
  },
  
  borderRadius: {
    none: 0,
    sm: 4,
    base: 8,
    md: 12,
    lg: 16,
    xl: 24,
    full: 9999,
  },
  
  shadows: {
    sm: {
      shadowColor: '#000',
      shadowOffset: {width: 0, height: 1},
      shadowOpacity: 0.05,
      shadowRadius: 2,
      elevation: 1,
    },
    base: {
      shadowColor: '#000',
      shadowOffset: {width: 0, height: 2},
      shadowOpacity: 0.1,
      shadowRadius: 4,
      elevation: 3,
    },
    lg: {
      shadowColor: '#000',
      shadowOffset: {width: 0, height: 4},
      shadowOpacity: 0.15,
      shadowRadius: 8,
      elevation: 5,
    },
  },
};
```

## Theme Provider

```typescript
// src/providers/ThemeProvider.tsx
import React, {createContext, useContext, ReactNode} from 'react';
import {DesignTokens} from '@config/designTokens';

interface ThemeContextType {
  colors: typeof DesignTokens.colors;
  typography: typeof DesignTokens.typography;
  spacing: typeof DesignTokens.spacing;
  borderRadius: typeof DesignTokens.borderRadius;
  shadows: typeof DesignTokens.shadows;
}

const ThemeContext = createContext<ThemeContextType | undefined>(undefined);

interface ThemeProviderProps {
  children: ReactNode;
}

export const ThemeProvider: React.FC<ThemeProviderProps> = ({children}) => {
  const theme = {
    colors: DesignTokens.colors,
    typography: DesignTokens.typography,
    spacing: DesignTokens.spacing,
    borderRadius: DesignTokens.borderRadius,
    shadows: DesignTokens.shadows,
  };

  return (
    <ThemeContext.Provider value={theme}>
      {children}
    </ThemeContext.Provider>
  );
};

export const useTheme = (): ThemeContextType => {
  const context = useContext(ThemeContext);
  if (!context) {
    throw new Error('useTheme must be used within a ThemeProvider');
  }
  return context;
};
```

## Responsive Design

```typescript
// src/utils/responsive.ts
import {Dimensions, PixelRatio} from 'react-native';

const {width: SCREEN_WIDTH, height: SCREEN_HEIGHT} = Dimensions.get('window');

// Based on iPhone 6/7/8 dimensions
const BASE_WIDTH = 375;
const BASE_HEIGHT = 667;

export const wp = (percentage: number): number => {
  const value = (percentage * SCREEN_WIDTH) / 100;
  return Math.round(PixelRatio.roundToNearestPixel(value));
};

export const hp = (percentage: number): number => {
  const value = (percentage * SCREEN_HEIGHT) / 100;
  return Math.round(PixelRatio.roundToNearestPixel(value));
};

export const normalize = (size: number): number => {
  const scale = SCREEN_WIDTH / BASE_WIDTH;
  const newSize = size * scale;
  return Math.round(PixelRatio.roundToNearestPixel(newSize));
};

export const isTablet = (): boolean => {
  return SCREEN_WIDTH >= 768;
};

export const getDeviceType = (): 'phone' | 'tablet' => {
  return isTablet() ? 'tablet' : 'phone';
};
```