How to change CSS root variable in React?

Is it possible to change CSS :root variable in ReactJS ? looking for solution to change --basecolor code based on what user selected from .change-me input color

Demo: https://codepen.io/anon/pen/RgXBEK

CSS

:root {
  --base: $primary;
}

React

changeTheme(e){
    console.log(e.target.value);
}

class App extends React.Component {
    render() {
        return (
            <div className="row">
                <div className="col-xs-12 text-center">
                    <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Aliquam voluptates ut eaque, voluptatum veniam nostrum sequi numquam sint, excepturi amet unde quis, ipsum ducimus reprehenderit eligendi pariatur animi esse sed.</p>
                    <input 
                      className="" 
                      type="color" 
                      onChange={this.changeTheme.bind(this)}
                      />
                    <br/><br/>
                </div>
            </div>
        );
    }
}

ReactDOM.render(<App />, window.document.getElementById('myDiv'));