This visualization shows the relationship between training steps and reward values across multiple data series, with each point annotated by its pollutant label. A natural cubic spline connects the data points, with circular markers emphasizing individual observations. The chart is built using React and D3 v5, employing `scaleTime` for the x-axis, `scaleLinear` for the y-axis, and the `line` generator with `curveNatural` for the smoothed path. Data is loaded asynchronously from an external CSV file via `d3.csv`, and the SVG output is styled with a Poppins font and custom tick colors.