This example renders a monthly sales area chart in SVG using D3 v7. It shows how sales values increase from January through December, with the area filled in steel blue beneath a line marking the data points. The chart manually constructs axes by applying `d3.axisLeft` for the y-axis and placing custom text labels for each month using `d3.scaleBand`. An `d3.area` generator defines the path, while `d3.scaleLinear` maps sales values to vertical positions, and margins control the layout.