CSS transitions | CSS transitions, CSS transforms and CSS animation
If you haven't used transitions before, here's a brief introduction. On the element you want to have animate, add the following CSS: #id_of_element { -webkit-transition: all 1s ease-in-out; -moz-transition: all 1s ease-in-out; -o-transition: all 1s ease-in-out; transition: all 1s ease-in-out; } There is a lot of duplication due to vendor prefixes - until the specification if finalised, this will persist.
http://css3.bradshawenterprises.com/transitions/
