Z-Index Does Not Work on Child Div - html

Question

Here's the fiddle: http://jsfiddle.net/gBQqQ/
Here's the html:
<div id='testtexture'>
<div id='testinside'>
<div style='vertical-align: top;' class='test'></div>
</div>
</div>
And the css:
.test {
width: 50px;
position: relative;
margin-left: auto;
margin-right: auto;
min-height: 130px;
height:auto;
padding-bottom:50px;
background:blue;
}
#testtexture {
width: 100%;
position: relative;
top: 10px;
}
#testinside {
z-index: 3;
background:red;
position:relative;
}
I do not see why there is an issue. I expect either there is something obvious that I am missing, or there is an underlying issue which means I cannot make the red div go above the blue div- maybe because it is a child of the blue div?

Answer 1

Generally not the best idea to have a child div you want to appear behind it's parent. Usually you would take the child div outside the parent to do this. Nonetheless it is possible. Add z-index:-1 to the child div and remove position:relative from the parent.
HTML
<div id='testtexture'>
<div id='testinside'>
<div class="test"></div>
</div>
</div>
CSS
.test {
position: relative;
z-index: -1;
width: 50px;
margin: 0 auto;
height: auto;
min-height: 130px;
padding-bottom: 50px;
background: blue; }
#testinside { background: red; }
See fiddle: http://jsfiddle.net/gBQqQ/1/
If you use firebug, you can see div.test is still there in the correct position behind it's parent. As a side note, the styling vertical-align you had on a div won't do anything.