This is possible without the use of extra mark-up through the use of multiple box-shadows:
box-shadow:
0 1px 2px #fff, /*bottom external highlight*/
0 -1px 1px #666, /*top external shadow*/
inset 0 -1px 1px rgba(0,0,0,0.5), /*bottom internal shadow*/
inset 0 1px 1px rgba(255,255,255,0.8); /*top internal highlight*/
http://jsfiddle.net/NPXfe/
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…