are there styling with classes in material ui code example

Example 1: material ui common styles

const useStyles = makeStyles({
  root: {
    color: 'red',
    '& p': {
      color: 'green',
      '& span': {
        color: 'blue'
      }
    }
  },
});

Example 2: material ui common styles

// with npm
npm install @material-ui/styles

// with yarn
yarn add @material-ui/styles