This example displays a single paragraph containing the text “Have a great day!” at the top of the page. It demonstrates a minimal D3.js setup by selecting the body element with `d3.select("body")`, appending a paragraph with `append("p")`, and setting its text content with `.text()`. The page loads D3 v7 from a CDN and performs no data binding or visualization, serving as a basic test area for confirming the library is working.