reagir importar o CSS de arranque
{/* The following line can be included in your src/index.js or App.js file*/}
import 'bootstrap/dist/css/bootstrap.min.css';
instalar o Suporte de arranque react
npm install react-bootstrap bootstrap
react native bootstrap
import Button from 'react-bootstrap/Button';
// or less ideally
import { Button } from 'react-bootstrap';