Left Align Label - Right Align Select Element (CSS)

Question

I have a form layout that I want to display the label aligned left and the form control aligned right. I have been trying to get it to work using a float:right on the form control (in this case a ) and then applying the clearfix class to it but the clearfix does not appear to be working on my select box.

Is there something wrong here or is clearfix not expected to work on a select element?

When I do this however, the select box still extends outside the bottom of the containing div.

My Code:

<style type="text/css">
#category-select {
left: 0px;
top: 0px;
width: 350px;
border: 1px solid #666;
}
select#category {
float: right;
}
select.clearfix:after {
    content: ".";
    display: block;
    height: 0;
    clear: both;
    visibility: hidden;
}
</style><!-- main stylesheet ends, CC with new stylesheet below... -->
<!--[if IE]>
<style type="text/css">
  select.clearfix {
    zoom: 1;  
  }  
</style>
<![endif]-->

<div id="triage">
    <div id="category-select">
          Category: 
          <select class="ipad-dropdown clearfix" id="category" name="category">
                <option value="A">A - Emergency
                <option value="B">B - Urgent
                <option value="C">C - ASAP
                <option value="D" selected>D - Standard
          </select>
    </div>
</div>