My first D3.js vizualization
A simple circle centered in an SVG canvas demonstrates the basic structure of a D3.js visualization. The code uses `d3.select` to access the SVG element, calculates its center from the `width` and `height` attributes, and appends a group (`g`) translated to that point. A circle with a radius of 100 pixels and an orange fill is then added to the group, showing how to position and style SVG shapes. The example is built with D3 v5 within a React framework, rendering entirely through SVG without any data binding or external datasets.