This example uses SVG and CSS to draw a smiling face, with a yellow circle for the head, black strokes, and two smaller circles for eyes. The mouth is created as a path using the d3.arc generator with a half-circle arc. D3 v5 selection and arc APIs are used to append and style SVG elements, while CSS sets the body margin and hides overflow on the page. The example demonstrates basic shape creation, attribute manipulation, and a custom arc path in a 960×500 viewport.