add bootstrap to react
//1.run following commnad in cmd: npm install bootstrap --save //you can now use bootstrap component. example: import { Button } from 'react-bootstrap'; //2.or add this to index.js: <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.6.0/dist/css/bootstrap.min.css" integrity="sha384-B0vP5xmATw1+K9KRQjQERJvTumQW0nPEzvF6L/Z6nronJ3oUOFUFpCjEUQouq2+l" crossorigin="anonymous" />