This interactive streamgraph visualizes quarterly median sale prices for houses and units with varying bedroom counts, sourced from the data.csv file. Users can reorder the legend categories through drag-and-drop, which triggers a redrawing of the stacked time-series chart via the `render` function. The visualization uses D3.js v6 for creating the SVG, scaling axes, and rendering the tooltip, while Sortable.js handles the reordering. The y-axis is fixed between -4,000,000 and 4,000,000 to accommodate the stacked values.