Edit in JSFiddle

var MyComponent = React.createClass({
  render: function() {
    return (
      <div>
        <h1>Simples Componente com React</h1>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nobis vel, laborum corporis quaerat eveniet iste obcaecati.</p>
      </div>
    );
  }
});

ReactDOM.render(
  <MyComponent />,
  document.body
);

              
h1 {
  color: #09195C;
}