# `useCss` React side-effect hook that changes [CSS dynamically][gen-5]. ## Usage ```jsx import {useCss} from 'react-use'; const Demo = () => { const className = useCss({ color: 'red', border: '1px solid red', '&:hover': { color: 'blue', }, }); return (
Hover me!
); }; ``` [gen-5]: https://github.com/streamich/freestyler/blob/master/docs/en/generations.md#5th-generation