I have the following title div setup, but when only the leftmost div has content, the red background for the title is not applied. Why is this, as the 'title' div has content, and its background should be red.

Head stuff:

<title>Into the Breech</title>
<link href="Styles/Reset.css" rel="stylesheet" type="text/css" />
<style type="text/css">
    body { font-family: Arial, Sans-Serif, System; }        
    #title { background-color: #F71831; font-weight: bold; }                    
    .title-segment-left { float: left; }
</style>

Body stuff:

<div id="title">
    <div id="menu-title" class="title-segment-left" style="width: 200px;">
        Menu
    </div>
   <div id="main-title" class="title-segment-left" style="width: auto;">
        Home Page
    </div>
    <div id="right-title" style="float: right;">
        Provantage Media Management System
    </div>
</div>