This example demonstrates a simple React application that renders a component containing two nested `<h1>` elements repeated in two `<div>` containers. The component, defined as `App`, uses ReactDOM.render to mount it into two separate DOM elements, `root` and `root1`, which have distinct background colors defined in CSS. The code imports React and ReactDOM from their production UMD bundles, showcasing basic component structure and multiple render targets within a single page.