CSS box shadow is used in casting shadows off block-level elements like <DIVS>. Both CSS rounded corners and CSS drop shadows can make website updates and maintenance  a breeze compared to cutting out images and using background elements.
 
  Hello this is a box shadow 
 
The structure of the above element is:
 
 
 -moz-box-shadow: 3px 3px 5px 6px #ccc; 
 
  -webkit-box-shadow: 3px 3px 5px 6px #ccc; 
 
  box-shadow: 3px 3px 5px 6px #ccc;
 
 
The structure consists of:
 
 
 - horizontal offset: a positive number indicates that shadow will fall on the right of the box
  
 - vertical offset: a positive number indicates that the shadow will be below the box
  
 - blur radius: This optional attribute indicates how blurred the shadow will be
  
 - spread radius: Increase the size of your CSS shadow with a positive number for this attribute
  
 - Color: You can dictate the color of your shadow as well