<!DOCTYPE html>
<!--
 | Simple vertical linear gradient where one color is fully transparent.
 -->
<html>
<head>
  <style>
    body {
      background: blue;
    }

    div {
      background: linear-gradient(white, transparent);
      width: 200px;
      height: 200px;
    }
  </style>
</head>
<body>
  <div></div>
</body>
</html>