Ryan Seddon 14 December 2009 FYI box-shadow has been removed from the CSS3 spec, http://www.w3.org/TR/css3-background/#the-box-shadow, for further discussion and most likely won’t make it back in. We are more likely see a new property like drop-shadow, http://www.bradclicks.com/cssplay/drop-shadow/Drop-Shadow.html, replace box-shadow. But of course it’s all still in discussion. Also Firefox 3.7 (Minefield) also has support for transitions through -moz-transition. Since transitions are a working draft probably would be wise to declare it like you have for box-shadow.