<figure class="circle"></figure>
body {
  width: 300px;
  margin: 20px auto;
}
.circle {
  display: block;
  background: black;
  border-radius: 100%;
  height: 300px;
  width: 300px;
  margin: 0;
  background: radial-gradient(circle at 100px 100px, #5cabff, #000);
}

External CSS

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External JavaScript

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