This example visualizes the temperature of a Walmart dataset over time from 2009 to 2019, combining a smooth line chart with a filled area beneath it to emphasize the trend. The visualization uses D3 v5 to parse CSV data, apply time and linear scales, and render SVG paths via `d3.line` and `d3.area` with `curveBasis` for smoothing. Axis ticks, labels, and gridlines are generated with `d3.axisBottom` and `d3.axisLeft`.