This example displays a line chart of sales data from 2018 to 2021, rendered as a light blue area chart. It uses D3 v7 APIs including `d3.scaleLinear`, `d3.extent`, `d3.axisBottom`, and `d3.area` to generate SVG paths inside a 600x400 viewport. The React integration is minimal, with a separate `index.jsx` file importing `select` from D3 to update a DOM element’s text content. The chart axes are drawn with default D3 ticks, and the area fill is hardcoded to `lightblue`.