This dark-themed chart compares average smartphone price and average battery life by brand, with white bars repainting the price scale on the left and a neon sky-blue line and dots marking battery life on the right. Built with React and D3 v6, the code uses `csv` to fetch data, `scaleBand` for the x-axis, `scaleLinear` for the two y-axes, and `axisBottom`, `axisLeft`, and `axisRight` for ticks. Animated hover states alter bar opacity and translate via CSS transitions, while the legend sits beneath the chart. Data comes from a remote gistfile.