CODE EXAMPLE FOR JAVASCRIPT

react material ui classname

const styles = makeStyles((theme: Theme) => ({
  container: {
    display: 'flex',
    flexWrap: 'wrap'
  },
  spacious: {   // class name
    padding: 10
  },
}));

const classes = useStyles();

// use it
<div className={`${classes.container} ${classes.spacious}`} >