I'm unable to remove the gap between the list items in IE7.

HTML:

```
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
    <head>
        <link type="text/css" rel="stylesheet" href="base.css" />
    </head>
    <body>
        <ul>
            <li>
                <div>row 1.1</div>
                <div>row 1.2</div>
            </li> 
            <li>
                <div>row 2.1</div>
                <div>row 2.2</div>
            </li> 
            <li>
                <div>row 3.1</div>
                <div>row 3.2</div>
            </li> 
        </ul>
    </body>
</html>

```

CSS:

```
ul
{
    padding: 0px;
    margin: 0px;    
}

li
{
    list-style-type: none;      
    width: 100%;    
    margin: 0px;
    padding: 0px;   
    border-bottom: 1px solid black;
    border-left: 1px solid black;
    border-right: 1px solid black;          
}

li:first-child
{
    border-top: 1px solid black;
}

li div
{
    float: left;
    width: 49.9%;
}

```