.fondo_logo { background-color: #333; height: 80px; width: 100%; padding-top: 8px;}
.contenitore_logo { margin: 0 auto 10px auto; transition: all 2s ease 0s; background-color: transparent; border-radius: 6px; padding: 28px; width: 100px; background-image: url("../img_firma/logo.png"); background-position: center center; background-repeat: no-repeat; height: 41px;}
.contenitore_logo:hover {  margin: 0 auto 10px auto; background-color: #fff; border-radius: 6px; padding: 28px; width: 150px; background-image: url("../img_firma/logo_hover.png"); background-position: center center; background-repeat: no-repeat; height: 41px;}