This D3.js example customizes the axes of a grouped bar chart using data from a CSV file. It visualizes nitrogen levels across different groups under normal and stress conditions, with the X-axis showing categories and the Y-axis representing values from 0 to 40. The code uses `d3.scaleBand` for the categorical X-axis and `d3.scaleLinear` for the Y-axis, with `d3.axisBottom` and `d3.axisLeft` to render the axes. The chart renders as SVG, applying custom tick sizes and colors via `d3.scaleOrdinal`.