content: import React from 'react';
  import { makeStyles } from '@material-ui/core/styles';
  import Badge from '@material-ui/core/Badge';
  import MailIcon from '@material-ui/icons/Mail';
  
  const useStyles = makeStyles((theme) => ({
    root: {
      '& > *': {
        margin: theme.spacing(1),
      },
    },
  }));
  
  export default function SimpleBadge() {
    const classes = useStyles();
  
    return (
      <div className={classes.root}>
        <Badge badgeContent={4} color="primary">
          <MailIcon />
        </Badge>
        <Badge badgeContent={4} color="secondary">
          <MailIcon />
        </Badge>
        <Badge badgeContent={4} color="error">
          <MailIcon />
        </Badge>
      </div>
    );
  }
  