JSFiddle - React, Tailwind, and code Playground
HTML
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="400" height="400">
<svg width="200" height="200">
<clipPath id="clip" clipPathUnits="userSpaceOnUse">
<ellipse cx="50%" cy="50%" rx="50%" ry="50%"/>
</clipPath>
</svg>
<rect width="100%" height="100%" fill="black"/>
<!-- If browser follows SVG spec a green circle with the same dimension as the black square would be visible. If the circle just overlaps a quarter of the black rect, the viewport of the clipPath is chosen instead. -->
<rect width="100%" height="100%" fill="green" clip-path="url(#clip)"/>
</svg>