Box-Shadow is a CSS property that is used to give shadow effects to HTML elements. We can use multiple CSS box-shadow properties to give an attractive 3D look to HTML elements.
We can attach one or more shadow with HTML elements. A CSS3 box-shadow property used X and Y offset relative to HTML element
 
<style>
/*example*/
.tdb-shadow{
	width:50px;
	height:50px;
	box-shadow:5px 0 0 5px gray;
}
</style><head>
	<style>
	.tdb-shadow{
		padding:15px 0;
		text-align:center;
		width:150px;
		border-radius:5px;
		box-shadow:2px 2px 5px 0px gray;
		}
	</style>
</head>
<body>
	<div class="tdb-shadow">Box-Shadow</div>
</body>