Rocket.Chat.ReactNative/app/views/RoomsListView/Search/styles.js

import { StyleSheet } from 'react-native';

export default StyleSheet.create({
	header: {
		zIndex: 2,
		flexDirection: 'row',
		alignItems: 'center',
		flex: 1
	},
	inputSearch: {
		flex: 1,
		fontSize: 18,
		color: '#fff'
	}
});