This example shows how two session rates vary over time on the same date, with overlapping blue and yellow semi-transparent areas drawn from a CSV of time-stamped values. The chart uses D3.js v3 to parse the data, apply a time-scale for the x-axis and a linear scale for the y-axis, and render the areas with `d3.svg.area()`. Axis labels, a title, and the areas are all drawn as SVG elements within a single `svg` group, with axes styled via `d3.svg.axis()`.