Material-UI checkboxes and radio buttons look so ugly

Hi! I was making a form using Formik in React (class-based component) and I got very ugly looking checkboxes and radio buttons. I have tried to dig-into the code using inspect element in Chrome, but still couldn't solve it. I have uploaded here the picture as well. I have used the same checkboxes in Angular from the same source, but works fine there. I don't know why it is not working in React.

The Material-UI is installed in package.json file as a dependency: "@material-ui/core": "^4.11.0"

Here is how I have written the code:

import React, { Component } from 'react';
import { Formik } from 'formik';
import { FormControlLabel, FormControl, FormLabel, Checkbox, Select, MenuItem, Radio, RadioGroup } from '@material-ui/core';

export default class FormikForm extends Component {
  componentDidMount() {}
  
  render() {
    return (
      <div className="formik-container">
        <Formik>
          <form>
            <FormControlLabel
              className="paper-checkbox col-md-12"
              control={
                <Checkbox
                  onChange={handleChange}
                  onBlur={handleBlur}
                  value="markAllDay"
                  color="secondary"
                  name="markAllDay"
                />
              }
               label="Book for the whole day"
            />
            
            <FormControlLabel
              className="paper-checkbox col-md-12"
              control={
                <Checkbox
                  onChange={handleChange}
                  onBlur={handleBlur}
                  value="markRecurring"
                  color="secondary"
                  name="markRecurring"
                />
              }
               label="Recurring event"
            />
            
            <FormControl component="fieldset">
              <RadioGroup
                row aria-label="eventType"
                name="recurEventType"
                onChange={handleChange}
              >
                <FormControlLabel
                  value="recur"
                  control={<Radio />}
                  label="Whole recur event"
                />
                <FormControlLabel
                  value="event"
                  control={<Radio />}
                  label="Only this event"
                />
              </RadioGroup>
            </FormControl>

          </form>
        </Formik>
      </div>
    );
  }

}

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>