I apologize in advance if this isn't where this post should be, I wasn't quite sure what it qualified as.

I'm having issues with some dropdown menu code i'm using on my blog. If I leave the font as 12px Helvetica, it works just fine. But once I change the size or font, I mouse over the tab and the dropdown menu disappears before I can click it. Can anyone help me fix this? I would like to use bold 24px Calligraffitti. Here is the code:

/*----- MBT Drop Down Menu ----*/

#mbtnavbar {
background: ##FFFFFF;
width: 960px;
color: #FFF;
margin: 0px;
padding: 0;
position: relative;
border-top:0px solid #960100;
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;
border-left:0px solid #333;
border-right:0px solid #333;
height:35px;
}
#mbtnav li a, #mbtnav li a:link, #mbtnav li a:visited {
color: #000000;
display: block;
font:normal 12px Helvetica, sans-serif;
margin: 0;
padding: 9px 12px 10px 12px;
text-decoration: none;

}
#mbtnav li a:hover, #mbtnav li a:active {
background: #FFFFFF;
color: #000000;
display: block;
text-decoration: none;
margin: 0;
padding: 9px 12px 10px 12px;



}
#mbtnav li {
float: left;
padding: 0;
}
#mbtnav li ul {
z-index: 9999;
position: absolute;
left: -999em;
height: auto;
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: #CCCCCC;
width: 120px;
color: #000000;
display: block;
font:normal 12px Helvetica, 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: #CCCCCC;
color: #000000;
display: block;
margin: 0;
padding: 9px 12px 10px 12px;
text-decoration: none;
}