materiul-ui按钮覆盖模式窗口react

import React, { useState } from 'react';
import Button from '@material-ui/core/Button';
import Dialog from '@material-ui/core/Dialog';
import DialogTitle from '@material-ui/core/DialogTitle';
import DialogContent from '@material-ui/core/DialogContent';
import DialogActions from '@material-ui/core/DialogActions';

function App() {
  const [open, setOpen] = useState(false);

  const handleClickOpen = () => {
    setOpen(true);
  };

  const handleClose = () => {
    setOpen(false);
  };

  return (
    <div>
      <Button variant="contained" color="primary" onClick={handleClickOpen}>
        打开窗口
      </Button>
      <Dialog open={open} onClose={handleClose}>
        <DialogTitle>窗口标题</DialogTitle>
        <DialogContent>
          <p>窗口内容</p>
        </DialogContent>
        <DialogActions>
          <Button onClick={handleClose} color="primary">
            关闭
          </Button>
        </DialogActions>
      </Dialog>
    </div>
  );
}

export default App;