medium-rebem-1.js

import React from 'react';

class Popup extends React.Component {
  render() {
    return (
      <div className={'popup' + (this.props.visible ? ' popup_visible' : '')}>
        <div className="popup__overlay"></div>
        <div className="popup__content">{this.props.children}</div>
      </div>
    );
  }
}