Try setting a percentage body font size and enclosing multiple name font families in quotes:
Edit style.css (line 356) and change:
body {
background:#DCDCDC none repeat scroll 0 0;
font-family:trebuchet ms,arial,helvetica,sans-serif;
margin:0;
padding:0 0 15px;
text-align:center;
}
to
body {
background:#DCDCDC none repeat scroll 0 0;
font-family:'trebuchet ms',arial,helvetica,sans-serif;
font-size:100.1%;
margin:0;
padding:0 0 15px;
text-align:center;
}
Let me know how if it works or not. This used to be an old IE bug, so I'm curious to see if it's something that could impact on Safari. I always set a body font on all designs, so it wouldn't be an issue I'd seen for a very long time.