Safari CSS positioning rules seem mutually exclusive to that of other browsers - html

Question

I have some CSS that looks fine in Chrome and Firefox, but is turning up a specific problem in Safari. The three divs/ul items are aligning properly in Chrome and Firefox, but are stacking directly on top of each other in Safari. To make it look right in Sf, I can make the left margin progressively larger between the three, but the result in FF and Chrome is that the divs go way off the page. I have tried a few hacks including this one:
#media screen and (-webkit-min-device-pixel-ratio:0){}
This didn't change anything. So here's the relevant HTML:
<ul id="nav">
<li class="nav_item"><div id= "work"> </div></li>
<li class="nav_item"><div id="about"> </div></li>
<li class="nav_item"><div id="contact"> </div></li>
</ul>
...And the CSS:
#work{ height: 50px;
width: 68px;
font-family: Helvetica, Arial, sans-serif;
font-size: 24px;
background-color: none;
background-image: url(work_1.png);
background-repeat: no-repeat;
background-size: 120%;
position: fixed;
text-align: center;
z-index: 201;
padding: 0px 0px 0px 0px;
margin: 1px 1px 1px 40px;
display: block;
clear: both;
float:right;}
#about{ height: 50px;
width: 68px;
font-family: Helvetica, Arial, sans-serif;
font-size: 24px;
background-color: none;
background-image: url(about.png);
background-repeat: no-repeat;
background-size: 120%;
position: fixed;
text-align: center;
z-index: 201;
padding: 0px 0px 0px 0px;
margin: 1px 1px 1px 40px;
display: block;
clear: both;
float: right;}
#contact{ height: 50px;
width: 84px;
font-family: Helvetica, Arial, sans-serif;
font-size: 24px;
background-color: none;
background-image: url(contact.png);
background-repeat: no-repeat;
background-size: 100%;
position: fixed;
text-align: center;
z-index: 200;
padding: 0px 0px 0px 0px;
margin: 1px 1px 1px 40px;
display: block;
clear: both;
float:right;}
#nav {
padding: 0px;
display:inline;
list-style-type:none;
margin: 30px 0px 0px 700px;
position:fixed;
width:600px;
}
.nav_item {
display:inline !important;
position:relative !important;
margin: 5px 5px 5px 150px;
width:100px;
display: inline !important;
}