CSS - Cut or merge shared border between divs - css

Question

How do I cut the shared border line between these two divs? I want the top small div to have border on three sides expect bottom and the larder div below that to have only top border but leaving the shared border. So it will look like a line running across both divs upper borders.
I tried overlaying top div on the bottom. But Not getting what I want.
.ihead {
background-color: #EEE;
width: 15em;
height: 3em;
text-align:center center;
border-top:1px solid black;
border-left:1px solid black;
border-right:1px solid black;
border-bottom:none;
}
.ibody {
background-color: #EEE;
width: 60em;
height:20em;
margin-top:3em;
border-top:1px solid black;
z-index: 10;
}
<div class="ihead"><h>Hello !</h></div>
<div class="ibody">......</div>
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Answer 1

The normal way you'd achieve this effect is to have the box on top move down over the top of it's border. In your example, you can achieve this by adding position: relative; bottom: -1px to your .ihead class and removing the margin-top: 3em from your .ibody class.
See the jsFiddle.

Answer 2

.bordered{
border: 1px solid black;
}
.bordered:not(:first-child){ //to merge borders between rows
border-top: none;
}
.bordered:not(:first-child){ //if you want to merge between columns
border-left: none;
}
<div class="bordered"><h1>Test1</h1></div>
<div class="bordered"><h1>Test2</h1></div>
<div class="bordered"><h1>Test3</h1></div>
This question was the first that popped up for me so i felt it was best if i answered it properly unlike the accepted answer above.
Using css:
.bordered{
border: 1px solid black;
}
.bordered:not(:first-child){ //to merge borders between rows
border-top: none;
}
.bordered:not(:first-child){ //if you want to merge between columns
border-left: none;
}