navbar not looking right in firefox

when i view this page in firefox

https://www.forex100.net/forextrading/index.php

the navbar at the top seems crunched together. there are four items in the navbar and the first two are stuck together, then a space, and then the next two are stuck together..

here is my css for the navbar:

#topbar{
margin: 5px 0px;
padding: 0px;
width: 778px;
overflow: auto;
background-color: #FFFF66;
border:1px solid #666666;
font-family: Verdana, Geneva, Arial, sans-serif;
font-size: 10px;
}

.navbar{
margin: 15px auto 5px auto;
padding: 3px 1px 2px 1px;
}

.navbar li {float:left; width: 5em; margin:15px 0 5px 0; display:inline; padding: 0;}
.navbar li a {margin: 0 10px 5px 10px; padding: 0;}
ul.navbar {list-style-type:none; margin:0 0 5px; text-align:center; padding: 0;}

.navbar a, .navbar a:visited {
cursor: pointer;
float: right;
font-weight: bold;
margin: 0px 10px 3px 10px;
color: #800091;
padding: 0;
}
.navbar a:link{
color: #0000FF;

anyone have a clue how to evenly space the list items in the navbar evenly apart?

they seem to look fine in IE browser….

tom