Overflow hidden doesn't seem to work

user1184100

I have a div containing text and image and text details within ul li and below is the html structure . I have applied overflow hidden to class .sbox but it doesn’t seem to work and the text details doesn’t appear to be hidden and overflown.

JSFiddle – http://jsfiddle.net/SAN6n/

HTML

<div id="content" class="contentList">
  <ul id="slist" class="storyList">    
    <li>
     <div id="storyBox1" class="sbox"> 
        <div class="boxContent" >
            <span class="overlay"><h5>Picture1 </h5></span>
            <div class="txtOverlay"><h3>This is spring and weather looks good ...</h3</div>
            <span><img src="http://img13.imageshack.us/img13/38/picture11tp.jpg"/></span>
         </div>
      </div>
     </li>    
    </ul>
</div>​

CSS

.storyList {
  width:100%;
  height:100%;   
}


.sbox {
float:left;
width:300px;
height:150px;
padding: 5px 7px 8px 5px;
margin-top:20px;
margin-right:40px;

background:white;
border:1px solid #DDD;

<!--border radius-->
-webkit-border-radius: 3px;
-moz-border-radius: 2px;
border-radius: 3px;

overflow: hidden;

}

.boxContent {

width:100%;
height:100%;
border: 1px solid #777;
}

.storyList li {
list-style:none;
}

.overlay {

float:left;
opacity: .7;
background: #000;  
height: 40px;  
width: 300px; 
position: absolute;    
}


h5{
float:left;
margin-top:0px;
padding:0 0 0 5px;
font-family: Tahoma;
letter-spacing: 0.5px;
font-size:30px;
color: white; 

}


.txtOverlay {
opacity: .7;
background: #000;  
height: 110px;  
width: 300px; 
position: absolute;        
margin-top:150px;
z-index:1;
font-weight:bold;
float:left;
font-family: OpenSansRegular;
letter-spacing: 0.5px;
font-size:10px;
color: white;

}​