text: import React, { useEffect } from "react";
  import { ThemeProvider } from "@material-ui/core/styles";
  import { BrowserRouter } from "react-router-dom";
  import theme from "./theme";
  import MainRouter from "./MainRouter";
  import { hot } from "react-hot-loader";
  
  const App = () => {
      useEffect(() => {
          const jssStyles = document.querySelector('#jss-server-side');
          if (jssStyles) {
              jssStyles.parentNode.removeChild(jssStyles);
          }
      }, []);
  
      return (
      <BrowserRouter>
          <ThemeProvider theme={theme}>
              <MainRouter />
          </ThemeProvider>
      </BrowserRouter>
      );
  }
  
  export default hot(module)(App);