This heatmap visualizes career-related data across grouped categories, with each cell colored on a scale from 1 to 100 using the `d3.scaleSequential` interpolator `d3.interpolateInferno`. Rows and columns are defined by the `group` and `variable` fields from the CSV data, rendered as an SVG via D3 v4. Hovering a cell triggers a custom tooltip showing the exact value, while the chart includes axis labels, a title, and a subtitle. The code loads data from a remote GitHub CSV source.