post title edit

Hi sup, I use the twenty twelve theme and i would like to make a change on the post style…i dont want just to change the post colour…i want the post colour to stay as it is generally,but i want it to change colour when i move my mouse on it.so i want the post title remain grey,but when you move your cersor on it to click it,i want it to turn green.how can i do this? (site: http://www.truthinsideofyou.org ) i reposted this in the past but i got no answer,so i would be grateful if you could help me.