This example demonstrates a single red rectangle drawn on an SVG canvas, with CSS-driven hover effects that transition its fill color to green and expand its stroke width over three seconds. The page uses a minimal HTML structure with inline CSS styling and JavaScript-free SVG markup. The rectangle’s initial appearance is defined by the `rect` element’s `x`, `y`, `width`, and `height` attributes, while the CSS `transition` property animates the `fill` and `stroke-width` changes on hover. The code relies solely on basic SVG and CSS, without any external libraries.