This heatmap visualizes abortion rates per 1,000 women aged 15–17 across U.S. states over multiple years, using a linear color scale from light gray to red to indicate rate intensity. The D3 v7 code loads data from a CSV and renders an SVG with `d3.scaleBand` for the x- and y-axes, `d3.axisBottom` and `d3.axisLeft` for ticks, and `d3.scaleLinear` for color encoding. It appends rectangles for each state-year pair, plus a legend and axis labels.