Reistlin, вроде на картинку похоже
.nav{
padding:3px 3px 3px 3px;
border:1px rgba(0,255,0,0.5) solid;
border-radius:4px;
padding: 0 0 -1em 0;
margin:2px;
box-sizing:border-box;
color:rgba(0,150,0,0.5);
background: -o-linear-gradient(rgba(0,200,0,0.3), rgba(0,200,0,0.9));
background: -webkit-linear-gradient(rgba(0,200,0,0.3), rgba(0,200,0,0.9));
background: -moz-linear-gradient(rgba(0,200,0,0.3), rgba(0,200,0,0.9));
}