content: import React from 'react';
  import PropTypes from 'prop-types';
  import Header from 'components/Header';
  import Footer from 'components/Footer';
  import classnames from 'classnames';
  
  import 'styles/core.scss';
  
  export default class CoreLayout extends React.Component {
    static propTypes = {
      strength: PropTypes.string,
      children: PropTypes.element.isRequired
    };
  
    render () {
      const level = `strength--${ [this.props.strength] }`;
      const classes = classnames('core-layout', {
        [level]: true
      });
  
      return (
        <div className={ classes }>
          <Header />
          <div className='core-layout__viewport container'>
            { this.props.children }
          </div>
  
          <Footer />
        </div>
      );
    }
  }
  