ellipse() CSS Function - Playground Example

<!DOCTYPE html><html><head><style type="text/css">/* The parent container provides the dimensions */
.ellipse-container {
  width: 400px;
  height: 250px;
  background-color: #f0f0f0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.blue-box {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #007bff, #00d4ff);
  
  /* - 40% is the horizontal radius
     - 25% is the vertical radius
     - 'at 50% 50%' centers the ellipse 
  */
  clip-path: ellipse(40% 25% at 50% 50%);
}</style></head><body><div class="ellipse-container">
  <div class="blue-box"></div>
</div></body></html>