This example demonstrates a minimal hot-reloading setup for a data visualization, displaying the text “Hello World!” at a large, adjustable font size. The single-page application runs entirely in the browser, with the `main` function receiving a container element and injecting the text via an HTML string. It uses no external libraries, relying on plain JavaScript and the DOM’s `innerHTML` property for rendering. The visualization supports live updates: altering the `fontSize` variable, even through alt-drag interaction, instantly re-renders the output without a page reload.