[WSG] a: class border width problem

[kvnmcwebn]

Hello list members,

Im doing something ignorant with the below code but i dont know what.

I want to add a round corner to the far left button of my navbar.

Im using the class ".corner" to insert a bg image in the button. 
It works apart from the stuborn bottom border that wont go away.
Any explanations for this? 

/*css*/

#drNav a {
 margin: 0px;
 float:left;
 display:block;
 _display:inline-block;
 padding: 4px 12px;
 color: #ffffff;
 text-decoration: none;
 width: auto; border-bottom: 4px solid #999999;
 _height:1%;
}


.corner {
background: url(../botcorn.gif) 
bottom left no-repeat; border-bottom: 0px;
}

/*html*/

<ul id="drNav">
      <li  class="corner"><a href="webhome.htm">  Web &amp <br/>
                                          Screen</a></li>
-best 
kvnmcwebn
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