.shadow {
  -moz-box-shadow: 5px 5px 5px #ccc;
  -webkit-box-shadow: 5px 5px 5px #ccc;
  box-shadow: 5px 5px 5px #ccc;
} 
- The horizontal offset of the shadow, positive  means the shadow will be on the right of the box, a negative offset will  put the shadow on the left of the box.
- The vertical offset  of the shadow, a negative one means the box-shadow will be above the  box, a positive one means the shadow will be below the box.
- The blur radius, if set to 0 the shadow will be sharp, the higher the number, the more blurred it will be.
- Color
 
Inner Shadow
.shadow {
   -moz-box-shadow:inset 0 0 10px #000000;
   -webkit-box-shadow:inset 0 0 10px #000000;
   box-shadow:inset 0 0 10px #000000;
}