z-Index stacking - position relative
by Ben Clayton
HTML
<div class="wrapper">
<div class="el1">
RED
</div>
<div class="el2">
BLUE
</div>
</div>
when applying z-index you need to explicitly put position:relative on the elements you are trying to stack in a certian order, if you want them stacked in a different order to the natural order the elements are in the html.
CSS
.wrapper {
position: relative;
}
.el1 {
color: red;
font-size: 120px;
z-index: 2;
position: relative;
}
.el2 {
color: blue;
top: -100px;
font-size: 100px;
z-index: 1;
position: relative;
}