This example demonstrates a minimal "Hello World" visualization in the VizHub V3 Runtime Environment. It renders a div element with centered text whose font size is controlled by a numeric variable. The code exports a `main` function that receives a container DIV and directly sets its innerHTML, illustrating the runtime's hot-reloading capabilities. No external libraries are used, only plain HTML and CSS within a JavaScript template literal. The visualization serves as a blank slate for building more complex graphics with interactive widgets.