your css is a little wonky:
#nav-primary {
clear: both;
margin: -25px 310px;
padding: 0 10px;
position: relative;
width: 100%;
z-index: 99;
}
#nav-primary ul, #nav-primary li {list-style: none;}
#nav-primary li a:link{
float: left;
display: block;
padding: 0 10px;
text-transform: lowercase;
font-family: bold;
font-size: 14px;
text-decoration: none;
}
#nav-primary li a:hover, a:active{
text-decoration:underline;
}
#nav-primary ul, #nav-primary li.current-menu-item a{text-decoration: underline;}
browsers will display things differently depending on how things are referenced. try to clean it up a bit and make it a little more specific. the last portion is a little confusing, you’re assigning all of the unordered list to be underlined along with the current list item…?