Hover a div behind another div

Question

Imagine this kind of strucure :

<div class="background">
  <div class="object"></div>
</div>
<div class="foreground"></div>

My foreground totally overlays my background In my CSS I would like to change object property on hover (ie .object:hover{} ) Is there way to do that in CSS without moving my object inside foreground or using js ?

Update : My css as asked.

.background { background:url('background.svg') no-repeat; }
.foreground { background:url('foreground.svg') no-repeat 50% 50%; }
.object {
 position: absolute;
 top:10px;
 left:10px;
 opacity:1;
}

.object:hover 
{
  opacity:0.5;
}

Answer 1

The answer is kind of. You can use sibling selector ( + ), but you must revert order of your divs.

Example CSS:

.background {
    position: absolute;
    width: 600px;
    height: 400px;
    background-color: red;
}

.foreground {
    position: absolute;
    width: 300px;
    height: 200px;
    left: 150px;
    top: 100px;
    background-color: green;
    z-index: 1;
}

.object {
    width: 600px;
    height: 400px;
}

.foreground:hover + .background .object {
    background-color: blue;
}

and HTML:

<div class="foreground"></div>
<div class="background">
    <div class="object"></div>
</div>

Working sample: http://jsfiddle.net/pBYwT/1/

Answer 2

div的较高z-index：要在顶部显示的悬停。