Page Widget How to - Invert a rounded corner

Question

We would like to know how to invert a rounded corner.

Answer


<!DOCTYPE html>
<html>
<head>
<style>
#my {<!--   w ww.j av a 2  s  . c  o  m-->
  width: 100px;
  height: 100px;
  background: #f00;
  -webkit-mask-image: radial-gradient(circle 10px at 0 0, transparent 0, transparent 20px, black 21px);
}
</style>
</head>
<body>
  <div id="my"></div>
</body>
</html>

The code above is rendered as follows: