import React from 'react';
import './App.css';
import {Heading} from 'rebass'
import { ThemeProvider } from '@emotion/react'
import styled from '@emotion/styled'

const theme = ...

function App() {
  return (
      <ThemeProvider theme={theme}>
        <div className="app">
          <Heading fontSize={7}>Hello</Heading>
        </div>
      </ThemeProvider>
  );
}