I think what you might be missing is a 'clearfix' solution within your css.
Updated Fiddle: http://jsfiddle.net/QzsL5/4/
.clearfix:after {
content: ".";
display: block;
clear: both;
visibility: hidden;
line-height: 0;
height: 0;
}
.clearfix {
display: inline-block;
}
html[xmlns] .clearfix {
display: block;
}
* html .clearfix {
height: 1%;
}
After implementing the above within your css, add the following class name 'clearfix' to your UL.