React Starter
This example demonstrates a minimal React starter setup that displays the text “Hello World!” in two places: as plain text in a `<pre>` element and as a large centered message rendered by React. The code directly manipulates the DOM by setting `textContent` on an element selected via `document.getElementById`, while also using React 16.10 and ReactDOM to mount a separate component into the `#root` div. No data visualization or additional libraries are involved.