<!DOCTYPE html>
<html>
<head>
<title>Title of the document</title>
<style>
.gradient {
height: 250px;
width: 250px;
background-color: blue;
background-image: radial-gradient( #ff0509, #fff700, #05ff33);
}
</style>
</head>
<body>
<div class="gradient"></div>
</body>
</html>