This example visualizes the happiness distribution of the top few countries using a pie chart, with each slice labeled with its percentage and a corresponding legend. The code loads CSV data via d3.csv, computes pie angles with d3.pie, and renders the chart as SVG paths using d3.arc. It applies an ordinal color scale with predefined hex and named colors, and formats the percentage labels using d3.format. The accompanying legend lists each country and its value, with bar rects and text elements styled via CSS classes.