how to position an element on top of another element?

Question

I have a menu and a search box. I would like to put the search box along with menu items. But my menu is being built in a different file in a div called 'custommenu' which uses the following css:

#custommenu {
  position:relative;
  z-index:999;
  font-size: 14px;
  margin: 0 auto;
  padding: 10px 16px;
  width: 918px;
  background-color: #FB0A51; 
  border-top-left-radius: 10px 10px; 
  -moz-border-top-left-radius: 10px 10px;
  border-top-right-radius: 10px 10px; 
  -moz-border-top-right-radius: 10px 10px;
}

Whereas I have my search box in a separate file which looks like this:

 <div class="header">
   some code
   <div class="quick-access">
      some code
   <php echo $this->getChildHtml('topSearch') ?>;
   </div>
 </div>

I tried adding the following to the css file so that the search box comes on top of the menu but it did not work

 .header .form-search { 
   position:absolute; 
   right:29px;  
   z-index:1000; 
   top: 80px;  
   width:315px;  
   height:30px;  
   padding:1px 0 0 16px; 
 }

Still the search box gets hidden behind the menu. I would like to have the search box n the menu. How do i do it?

EDIT: Here's the css of the div's which contains the search box,

 .header { width:930px; margin:0 auto; padding:10px; text-align:right; position:relative; z-index:10; border-top:3px solid #3C3C42;}
 .header .quick-access { float:right; width:600px;margin-top:-125px; padding:28px 10px 0 0; }
 .header .form-search { position:relative; top: 100px;left: 300px; z-index:9999; width:315px; height:30px; padding:1px 0 0 16px; }

And this is how it looks right now, (purple links - quick access, white box is search which is going behind the pink 'custommenu' area. I would like to have the white box on the pink area. And all of this is inside 'header')

Answer 1

@all

Sorry for replying very late. But I found the solution after a little bit of fiddling. I set the z-index of my header to a higher value than my custommenu. Since my header contains the search box it needed to have a higher value for the search box to come over the menu.

The code looks like this now

.header{ position: relative; z-index: 4000; }
 .header search { position: relative; z-index: 99999; }
.custommenu { position: relative; z-index: 1000 ;}

This perfectly got my search box on top of my menu aligned. Thanks again for all those who helped. Appreciate it.