This bubble chart compares smartphone brands across battery life (hours), screen size (inches), and charging speed (watts). Each circle’s x-position encodes battery life, y-position encodes screen size, and its area encodes charging speed, with colors distinguishing brands. The D3.js v7 code uses `d3.scaleLinear` for axes, `d3.scaleSqrt` for bubble sizing, and `d3.scaleOrdinal` with `d3.schemeCategory10` for colors. Data comes from a hardcoded CSV-like array. A hover tooltip displays exact values for each smartphone model.