CSS Layering Quirks

Question

Alright, so I've got a couple divs wrapped in a container. The two interior divs overlap each over by 15px; The problem is I'm not able to layer them like I want.

 <div class="headerButtons">
    <div id="WorkTableButton" class="WorkTableButtonActive">
     Work Table
    </div>
    <div id="additionalCostsButton" class="additionalCostsButtonInactive">
     Additional Costs
    </div>
</div>

and the CSS looks like so,

.headerButtons{
    margin:auto;
    text-align:center;
}
.headerButtons div{
    text-align:center;
    height:27px;
    text-indent:-9999%;
    display:inline-block;
    cursor:pointer;
}

#WorkTableButton{
    width: 195px;
}

.WorkTableButtonActive{
    background: url(ui_images/WorkTableActiveButton.png) no-repeat;
    z-index:99999;
}

#additionalCostsButton{
    width: 192px;
    position:relative;
    left: -15px;

}
.additionalCostsButtonInactive{
    background: url(ui_images/AdditionalCostsInnactiveButton.png) no-repeat;
    z-index:0;
}

The problem is, the #WorkTableButton div still shows up behind the #additionalCostsButton even though the WorkTableButtonActive class is applied to it which layer the div above the other... Right?

What am I doing wrong?

Thanks,

Answer 1

Change

#additionalCostsButton {
     left: -15px;
}

to

#additionalCostsButton {
     margin-left: -15px;
}

Answer 2

The z-index property only works on elements that have been specifically positioned.

You need to add a position to your #WorkTableButton, like this:

#WorkTableButton{
    width: 195px;
    position: relative;
}

#additionalCostsButton will appear behind #WorkTableButton after that.