This example demonstrates a simple animated smiley face built with D3 v6 and rendered as SVG. It shows how to structure a basic D3 project using ES6 imports and a separate bundle file, with the page loading from an HTML shell and stylesheet. The visualization uses `d3.select` and `d3.arc` to construct the face, eyes, and a mouth, while a chained `transition().duration()` animates the left eyebrow rising and falling. The fixed SVG canvas is 960 by 500 pixels, and all elements are positioned via explicit width and height attributes.