Drop-shadows are easy enough to create using pseudo-elements. It’s a nice and robust way to progressively enhance a design. The article: CSS drop-shadows without images, is a summary of the technique and some of the possible appearances.
There is no need for extra markup, the effect can be applied to a single element. A couple of pseudo-elements are generated from an element and then pushed behind it.
Requirements: Firefox 3.5+, Chrome 5+, Safari 5+, Opera 10.6+
License: License Free