is it best to have styles in react native code example

Example 1: react native styles for both platforms

import { Platform, StyleSheet } from 'react-native';

const styles = StyleSheet.create({
  container: {
    flex: 1,
    ...Platform.select({
      ios: {
        backgroundColor: 'red'
      },
      android: {
        backgroundColor: 'green'
      },
      default: {
        // other platforms, web for example
        backgroundColor: 'blue'
      }
    })
  }
});

Example 2: styles in react native

//Import
import { StyleSheet} from 'react-native';

//Add style in React native component this way
<View style={styles.container}>
</View>
  
//create your style this way
const styles = StyleSheet.create({
  container: {
    marginTop: 50,
  },
});