Test HTML
A grid of 50 black rounded squares displays a minimalist visual pattern across the viewport. Each square is a plain HTML `div` element, styled with CSS properties including `background-color`, `width`, `height`, and `border-radius`. A JavaScript `for` loop programmatically creates and appends each square to the document body using `document.createElement` and `document.body.append`. The layout uses flexbox with `flex-wrap` to arrange the squares in rows. The page contains no external libraries, relying solely on native DOM manipulation and inline CSS.