Used in casting shadows off block-level elements (like divs).

.shadow {
  box-shadow: 5px 5px 5px #ccc;
  -moz-box-shadow: 5px 5px 5px #ccc;
  -webkit-box-shadow: 5px 5px 5px #ccc;
}
  1. 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.
  2. 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.
  3. The blur radius, if set to 0 the shadow will be sharp, the higher the number, the more blurred it will be.
  4. Color

Example

Inner Shadow

.shadow {
   box-shadow:inset 0 0 10px #000000;
   -moz-box-shadow:inset 0 0 10px #000000;
   -webkit-box-shadow:inset 0 0 10px #000000;
}

Example