Vertical Lines Appearing HTML/CSS - html

Question

I'm trying to put a drop down menu on Blogger and found one that actually works. The only problem is that these three thin black vertical lines appear underneath the menu. I can't figure out what in the code is causing them, or if it's something else entirely. I've tried editing the borders, but it doesn't seem to do anything. The site uses HTML/CSS.
/----- MBT Drop Down Menu ----/
#mbtnavbar {
background: #000000;
width: 960px;
color: #FFF;
margin: 0px;
padding: 0;
position: relative;
height:35px;
}
#mbtnav {
margin: 0;
padding: 0;
}
#mbtnav ul {
float: left;
list-style: none;
margin: 0;
padding: 0;
}
#mbtnav li {
list-style: none;
margin: 0;
padding: 0;
height:35px;
}
#mbtnav li a, #mbtnav li a:link, #mbtnav li a:visited {
color: #FFF;
display: block;
font:normal 18px josefin sans; margin: 0;
padding: 17px 12px 10px 12px;
text-decoration: none;
}
#mbtnav li a:hover, #mbtnav li a:active {
background: #E3E4FA;
color: #000000;
display: block;
text-decoration: none;
margin: 0;
padding:17px 12px 10px 12px;
}
#mbtnav li {
float: left;
padding: 0;
}
#mbtnav li ul {
z-index: 9999;
position: absolute;
left: -999em;
height: 100%;
width: 160px;
margin: 0;
padding: 0;
}
#mbtnav li ul a {
width: 140px;
}
#mbtnav li ul ul {
margin: -25px 0 0 161px;
}
#mbtnav li:hover ul ul, #mbtnav li:hover ul ul ul, #mbtnav li.sfhover ul ul, #mbtnav li.sfhover ul ul ul {
left: -999em;
}
#mbtnav li:hover ul, #mbtnav li li:hover ul, #mbtnav li li li:hover ul, #mbtnav li.sfhover ul, #mbtnav li li.sfhover ul, #mbtnav li li li.sfhover ul {
left: auto;
}
#mbtnav li:hover, #mbtnav li.sfhover {
position: static;
}
#mbtnav li li a, #mbtnav li li a:link, #mbtnav li li a:visited {
background: #000000;
width: 120px;
color: #FFF;
display: block;
font:normal 15px josefin sans, sans-serif;
margin: 0;
padding: 9px 12px 10px 12px;
text-decoration: none;
z-index:9999;
border-bottom:1px dotted #333;
}
#mbtnav li li a:hover, #mbtnavli li a:active {
background: #E3E4FA;
color: #000000;
display: block; margin: 0;
padding: 9px 12px 10px 12px;
text-decoration: none;
}