This example displays three months of daily sales data for three products as a multi-series line chart, then presents advertising budget as a bar chart with a profit margin line overlaid on a secondary y-axis. The code uses `d3.scaleBand`, `d3.scaleTime`, `d3.line`, and `d3.axisBottom` for the D3 v7 SVG visualizations. Data from the CSV file is parsed with `d3.csv` and `d3.timeParse`, and the charts include gridlines, legends, and annotations highlighting maximum values.