Fork of #HAW: Birthday data viz
This fork of a "HAW: Birthday data viz" example presents daily birth counts across several years as a monthly line chart. A color-coded year selector lets the user switch between datasets, each rendered as a distinct colored line with a matching gradient area beneath it. The visualization is built with React for state and UI, while D3 v7 (via `csv`, `scaleTime`, `scaleLinear`, `line`, `axisBottom`, and `axisLeft`) handles data parsing and chart rendering. The code loads German-format dates from a CSV file, computes day-of-year values, and displays the time series on an SVG canvas with a dark theme.