Im trying to make the text links in the navbar,
http://www.urturt.com/
to be images, what part of the css to I need to modify for this to happen, so far I tried

div.nav {
height: 45px;
}
.header .nav li a{
text-decoration: none;
font-size:20px;
font-weight:300;
text-indent:-999px
}

.nav li.page-item-896 a {
background-image:url(images/nav_shop.png);
width:100px;
}