Box shadow for bottom side only
You can do the following after adding class one-edge-shadow
or use as you like.
.one-edge-shadow {
-webkit-box-shadow: 0 8px 6px -6px black;
-moz-box-shadow: 0 8px 6px -6px black;
box-shadow: 0 8px 6px -6px black;
}
Source
You have to specify negative spread
in the box shadow to remove side shadow
-webkit-box-shadow: 0 10px 10px -10px #000000;
-moz-box-shadow: 0 10px 10px -10px #000000;
box-shadow: 0 10px 10px -10px #000000;
Check out http://dabblet.com/gist/9532817 and try changing properties and know how it behaves