This bubble chart visualizes product data from a CSV file, plotting price on the x-axis against quantity sold on the y-axis. Each circle’s radius represents profit margin using `d3.scaleSqrt`, while color encodes the product category through `d3.scaleOrdinal` with `d3.schemeTableau10`. The SVG rendering uses `d3.axisBottom`, `d3.axisLeft`, and the `d3.select` and `.enter()` APIs to draw circles, with a custom HTML legend positioned in the upper right corner.