CodePen Embed - Simple example of margin collapsing

<div class="box-a"></div>
<div class="box-b"></div>

div {
   background-color: lightseagreen;
   height: 100px;
}

.box-a {
   margin-bottom: 30px;
}

.box-b {
   margin-top: 20px;
}

This Pen is owned by Guillermo Peralta on CodePen.

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