This example draws a simple smiley face using SVG shapes styled with CSS. The visualization creates a large yellow circle for the face, adds two smaller black circles for eyes, and uses CSS to set page margins and a large title font size. The D3 v7 library is loaded via UNPKG, and the code imports the `select` function from `d3` to select the SVG element and append circles with attributes for radius, position, fill, and stroke.