Need to Justify a list

Unfortunately, the site I’m working on isn’t live yet so I can’t provide a link. I apologize.

I’m using the following code to tweak the archive page. The list it generates aligns left and I really need it to have a justified alignment, without changing anything else in terms of appearance. I’ve tried various suggestions I’ve found via Google and looking through the forum here but nothing works and my coding experience is limited. I’d really appreciate some help with this. Thanks in advance.

/*-----------------------------------------------------------------------------------*
/* = Archives Page Tweaks
/*-----------------------------------------------------------------------------------*/
ul.bycategories {
margin: 0;
padding: 0;
width: 100%;
}
ul.bycategories li {
list-style: none;
list-style-type: none;
margin: 0;
padding: 0
}
ul.bycategories li a {
list-style: none;
list-style-type: none;
margin: 0 14px 14px 0;
float: left;
background: #ffffff;
border: 1px solid #8b8b8b;
color: #191919;
padding: 5px 10px;
border-radius: 5px;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
}
ul.bycategories li a:hover{
text-decoration: none;
background: #5e9321;
color: #ffffff;
}
.clear{clear: both;}