This example demonstrates a minimal React application that renders a static greeting message. The interface displays the text “Hello React!” inside a styled container, showcasing the basic structure of a React component. The code imports the React and ReactDOM libraries, defines an `App` component that returns a `div` element with a CSS class, and uses `ReactDOM.render()` to mount the component into the root element of the page. The visible output is solely the styled text, with no interactive or dynamic behavior present.