This example shows a monthly time series as a simple line chart with circular markers for each data point, drawn using SVG. D3 v4 scales, a time parser, and a line generator map the dataset’s dates and values to positions. On mouseover, the code highlights the hovered circle in red, reveals its dashed vertical guide, and displays its numeric value with a font-size transition; mouseout reverses the effect. The data comes from a local JSON file, and all interactions rely on D3 selections and transitions.