This fork of an area chart visualizes bike users from 2012 to 2022, combining a smooth line and a filled area to show yearly trends. The visualization uses D3 v5 with SVG rendering, employing `d3.line` and `d3.area` generators with `curveBasis` for smoothing, plus `scaleLinear` axes for both dimensions. Data is loaded from a CSV via `d3.csv`, with users and years parsed as numbers. Axis labels and gridlines are styled through CSS, while the area fill and line stroke are defined by the `.line-chart` and `.area-chart` classes.