mobileapp/App.js

import 'react-native-gesture-handler';
import React from 'react';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import { DefaultTheme, Provider } from 'react-native-paper'
import MainStackNavigator from './navigation/MainStackNavigator';

const theme = {
  ...DefaultTheme,
  colors: {
    primary: '#df3f3f',
    accent: 'white',
  },
}

const App = () => {
  return(
    <Provider theme={theme}>
      <NavigationContainer>
        <MainStackNavigator />
      </NavigationContainer>
    </Provider>
  )
}

export default App;