This interactive timeline visualizes a patient’s diastolic pressure over time, rendered as a red area chart with a smoothed line. Users can hover over the chart to update a vertical selection line, with a tooltip displaying the date and value. The visualization is built with D3 v5, using `scaleTime`, `scaleLinear`, `line`, and `area` generators, along with a brush for zooming. Data is loaded from a CSV file and filtered by the selected metric.