css/css-backgrounds/box-shadow-radius-generated.html

<!DOCTYPE html>
<title>Box Shadow Border Radius (Outset)</title>
<link rel="help" href="https://www.w3.org/TR/css-backgrounds-3/#shadow-shape">
<link rel="match" href="box-shadow-radius-generated-ref.html">
<!-- Allow differences of antialised pixels along rounded edges -->
<meta name="fuzzy" content="0-32;0-128">
<meta name="variant" content="?width=50&height=50&spread=50&radius=0px">
<meta name="variant" content="?width=50&height=50&spread=50&radius=1px">
<meta name="variant" content="?width=10&height=10&spread=70&radius=100%">
<meta name="variant" content="?width=200&height=40&spread=50&radius=100px%20/%2020px">
<meta name="variant" content="?width=200&height=40&spread=50&radius=20px%20/%204px">
<meta name="variant" content="?width=300&height=50&spread=30&radius=15px">
<meta name="variant" content="?width=300&height=50&spread=30&radius=25px">
<meta name="variant" content="?width=300&height=60&spread=30&radius=20px%2020px%2040px%2040px">
<meta name="variant" content="?width=300&height=50&spread=30&radius=1px%201px%2049px%2049px">
<meta name="variant" content="?width=300&height=60&spread=30&radius=0px%200px%2030px%2030px">
<meta name="variant" content="?width=300&height=50&spread=30&radius=50%">
<meta name="variant" content="?width=300&height=50&spread=30&radius=50%%2050%%201px%2050%">
<meta name="variant" content="?width=200&height=40&spread=50&radius=10%%2090%%205%%">
<meta name="variant" content="?width=200&height=40&spread=50&radius=0%2050%%2050%">
<meta name="variant" content="?width=250&height=30&spread=100&radius=10px">
<style>
  #target {
    position: absolute;
    top: 100px;
    left: 100px;
    width: calc(var(--width) * 1px);
    height: calc(var(--height) * 1px);
    border-radius: var(--radius);
    box-shadow: 0 0 0 calc(var(--spread) * 1px) black;
    background: green;
  }
</style>

<script>
  for (const param of new URL(location.href).searchParams)
    document.documentElement.style.setProperty(`--${param[0]}`, param[1]);
</script>

<div id="target"></div>