添加react-router-dom之后，我的github页面没有显示任何内容

npm install react-router-dom

import { BrowserRouter as Router, Route, Switch } from 'react-router-dom';

import React from 'react';
import { Route, Switch } from 'react-router-dom';
import Home from './Home';
import About from './About';
import NotFound from './NotFound';

const App = () => {
  return (
    <Switch>
      <Route exact path="/" component={Home} />
      <Route path="/about" component={About} />
      <Route component={NotFound} />
    </Switch>
  );
};

export default App;

import React from 'react';
import { BrowserRouter as Router } from 'react-router-dom';
import App from './App';

const Root = () => {
  return (
    <Router>
      <App />
    </Router>
  );
};

export default Root;