Add CSS box shadow around the whole DIV

You're offsetting the shadow, so to get it to uniformly surround the box, don't offset it:

-moz-box-shadow: 0 0 3px #ccc;
-webkit-box-shadow: 0 0 3px #ccc;
box-shadow: 0 0 3px #ccc;

Yes, don't offset vertically or horizontally, and use a relatively large blur radius: fiddle

Also, you can use multiple box-shadows if you separate them with a comma. This will allow you to fine-tune where they blur and how much they extend. The example I provide is indistinguishable from a large outline, but it can be fine-tuned significantly more: fiddle

You missed the last and most relevant property of box-shadow, which is spread-distance. You can specify a value for how much the shadow expands or contracts (makes my second example obsolete): fiddle

The full property list is:

box-shadow: [horizontal-offset] [vertical-offset] [blur-radius] [spread-distance] [color] inset?

But even better, read through the spec.