[RESOLVED] Having problems with :last-child

[landysaccount]

I can't get this code to work correctly in any browser:

.boxes-wrapper{
    width:960px;
  }
  .section_box{
    width:311px;
    margin:0 10px 10px 0;
    height:200px;
	  background:#f3f3f3;
	  float:left;
  }
  
  .boxes-wrapper .section_box:last-child{
    margin:0;
    background:#000;
  }

<div class="boxes-wrapper">       
                   
  <div class="section_box">
    
  </div>
  
  <div class="section_box">
    
  </div>
  
  <div class="section_box">
    
  </div>
  <div class="clear"></div> 
         
</div>     

The last "section_box" never changes color...

What am I doing wrong?

Thanks in advanced for your time and help.

[landysaccount]

I fixed it using nth-child....

Thanks.