A stacked bar chart displays the normalized proportions of horsepower, torque, and highway MPG for six car makes, with each bar summing to 100%. The x-axis uses percentage formatting, and a categorical color legend identifies the three metrics. Built with D3 v7, the chart uses `d3.stack()` to compute stacked series, `d3.scaleBand()` for the categorical y-axis, and `d3.scaleLinear()` for the numeric x-axis. Data is loaded from an inline array derived from the provided CSV, and SVG rectangles render each segment.