This visualization shows how the average pH, citric acid, and residual sugar levels of red wine change across different alcohol percentages. The data is grouped by rounded alcohol content, with each metric averaged per group and plotted as a multi-line chart. Built with D3 v7, the code uses `d3.rollups` for aggregation, `d3.scaleLinear` and `d3.scaleOrdinal` for scaling, and `d3.line` to generate the paths, with axes rendered via `d3.axisBottom` and `d3.axisLeft`. The source CSV is loaded directly from a GitHub gist.