Add line-height: 30px;
to .menuitem in CSS.
Edit I've tried with this CSS:
.menuitem a {
width:auto;
font-size:30px;
line-height:100%;
z-index:9999;
float:left;
padding: 5px 10px 5px 10px;
color: #fff;
background-color: #000;
}
and it should work - but I've got almost 100% same result only when Google font is commented out and Arial is used. So it's obviously a difference in the font-rendering itself. I'm also always going crazy becuase of such differences ;)