<div class="box"></div>
body {
  margin: 0;
  padding: 0;
  height: 100vh;
}

.box {
  width: 100%;
  height: 240px;
  background: radial-gradient(circle at 50% 330%, orange, orange 80%, #333 80%);
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.