如何在React Native中进行主题和样式的管理？

const theme = {
  colors: {
    primary: '#007aff',
    background: '#f8f8f8',
    text: '#333333',
  },
  fontSizes: {
    small: 12,
    medium: 16,
    large: 20,
  },
};

import { ThemeContext } from './ThemeContext';

const { colors, fontSizes } = useContext(ThemeContext);

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: colors.background,
    justifyContent: 'center',
    alignItems: 'center',
  },
  text: {
    fontSize: fontSizes.large,
    color: colors.text,
  },
});

<View style={styles.container}>
  <Text style={styles.text}>Hello, world!</Text>
</View>