A US state heatmap visualizes minimum wage values over time. Users select among four wage metrics—effective minimum wage, effective minimum wage in 2020 dollars, federal minimum wage, or state minimum wage—from a dropdown. D3 v7 renders an SVG grid with years on the x-axis and states on the y-axis, where each rectangle's color is mapped via `d3.scaleSequential` with `d3.interpolateTurbo`. Hovering a cell triggers a tooltip showing the state, year, and precise numeric value. Data is loaded remotely from a CSV hosted on GitHub.