css/css-backgrounds/box-shadow-radius-000.html

<!DOCTYPE html>
<title>Box Shadow Border Radius (Outset)</title>
<link rel="author" title="Elika J. Etemad" href="http://fantasai.inkedblade.net/contact">
<link rel="help" href="https://www.w3.org/TR/css-backgrounds-3/#shadow-shape">
<link rel="match" href="box-shadow-radius-000-ref.html">
<!-- Allow differences of antialised pixels along rounded edges -->
<meta name="fuzzy" content="0-25;0-80">

<style>
  body > div {
    /* Isolate tests from each other */
    position: relative;
    width: 100px;
    height: 100px;
    float: left;
  }
  div > div {
    position: absolute;
    box-sizing: border-box;
    /* opacity: 0.7; /* uncomment this line for debugging */
  }

  .floor > .test {
    color: silver;
  }
  .trap > .test {
    color: red;
  }

  .floor > .ref {
    border: solid red;
    width: 58px;
    height: 58px;
    top: 21px;
    left: 21px;
  }
  .trap > .ref {
    border: solid silver;
    width: 62px;
    height: 62px;
    top: 19px;
    left: 19px;
  }

  /* Keep tests centered by (top|left)*2 + (width|height) = 100.
     Keep tests consistent spread + (width|height) = 60
     Floor = spread - 2px
     Trap = spread + 2px */

  .once > .test {
    border-radius: 10px;
    box-shadow: 0 0 0 10px;
    /* shadow radius = 20px */
    top: 30px; left: 30px;
    width: 40px; height: 40px;
  }
  .once > .ref {
    border-radius: 20px;
  }
  .once.floor > .ref {
    border-width: 8px;
  }
  .once.trap > .ref {
    border-width: 12px;
  }

  .twice > .test {
    border-radius: 10px;
    box-shadow: 0 0 0 5px;
    /* shadow radius = 15px */
    top: 25px; left: 25px;
    width: 50px; height: 50px;
  }
  .twice > .ref {
    border-radius: 15px;
  }
  .twice.floor > .ref {
    border-width: 3px;
  }
  .twice.trap > .ref {
    border-width: 7px;
  }

  .half > .test {
    border-radius: 8px;
    box-shadow: 0 0 0 16px;
    /* shadow radius = 21px */
    top: 36px; left: 36px;
    width: 28px; height: 28px;
  }
  .half > .ref {
    border-radius: 21px;
  }
  .half.floor > .ref {
    border-width: 14px;
  }
  .half.trap > .ref {
    border-width: 20px;
  }

  .fourth > .test {
    border-radius: 5px;
    box-shadow: 0 0 0 20px;
    /* shadow radius = 14.45px */
    top: 40px; left: 40px;
    width: 20px; height: 20px;
  }
  .fourth > .ref {
    border-radius: 15px;
  }
  .fourth.floor > .ref {
    border-width: 18px;
  }
  .fourth.trap > .ref {
    border-width: 23px;
  }

  .eighth > .test {
    border-radius: 2px;
    box-shadow: 0 0 0 16px;
    /* shadow radius = 5.28 */
    top: 36px; left: 36px;
    width: 28px; height: 28px;
  }
  .eighth > .ref {
    border-radius: 5.28px;
  }
  .eighth.floor > .ref {
    border-width: 14px;
  }
  .eighth.trap > .ref {
    border-width: 18px;
  }


</style>

<p>Test passes if there is no red.

<div class="once floor">
  <div class="ref"></div>
  <div class="test"></div>
</div>
<div class="once trap">
  <div class="test"></div>
  <div class="ref"></div>
</div>

<div class="twice floor">
  <div class="ref"></div>
  <div class="test"></div>
</div>
<div class="twice trap">
  <div class="test"></div>
  <div class="ref"></div>
</div>

<div class="half floor">
  <div class="ref"></div>
  <div class="test"></div>
</div>
<div class="half trap">
  <div class="test"></div>
  <div class="ref"></div>
</div>

<div class="fourth floor">
  <div class="ref"></div>
  <div class="test"></div>
</div>
<div class="fourth trap">
  <div class="test"></div>
  <div class="ref"></div>
</div>

<div class="eighth floor">
  <div class="ref"></div>
  <div class="test"></div>
</div>
<div class="eighth trap">
  <div class="test"></div>
  <div class="ref"></div>
</div>