Overlapping divs

Question

I require 2 overlapping divs, which look like the one below.

    ------------------------------------
   |                      |             |
   |   ------------------ |             |
   |  '                  '|             |
   |  '                  '|             |
   |  '                  '|             |
   |  '                  '|             |
   |  '                  '|             |
   |  '                  '|             |
   |  '                  '|             |
   |  --------------------|             |
   |  '                  '|             |
   |  '                  '|             |
   |   -------------------|             |
   |                      |             |
   |                      |             |
    ------------------------------------

But somehow am unable to get it. here is the place am fiddling out Can anyone tell me where am I going wrong.

Edit 1: I have a left div and a right div. The left div has the overlapping div. Right div is a normal div. I guess most of you are confused and thing the right div to be the overlapping one, there are 2 divs in the left div i need those to overlap.

Sorry to confuse you all.

Answer 1

I think you want something like this:

html

<div class="parent">
  <div class="a"></div>
  <div class="b"></div>
</div>

css

.parent {
  position: relative;
}

.a {
  position: absolute;
  width: 100px;
  height: 100px;
  z-index: 100;
  background: red;
}

.b {
  position: absolute;
  width: 80px;
  height: 180px;
  z-index: 110;
  left: 10px;
  background: blue;
  top: 10px;
}

Edit: in your case parent = contentContainer, a/b = leftContainer/rightContainer