如何在React中编辑或导入CSS？

import React from 'react';

const MyComponent = () => {
  const styles = {
    color: 'red',
    fontSize: '16px',
    fontWeight: 'bold',
  };

  return <div style={styles}>Hello World</div>;
};

export default MyComponent;

import React from 'react';
import styles from './MyComponent.module.css';

const MyComponent = () => {
  return <div className={styles.myClass}>Hello World</div>;
};

export default MyComponent;

import React from 'react';
import styled from 'styled-components';

const StyledDiv = styled.div`
  color: red;
  font-size: 16px;
  font-weight: bold;
`;

const MyComponent = () => {
  return <StyledDiv>Hello World</StyledDiv>;
};

export default MyComponent;