CSS: background-color only inside the margin

Question

I have searched for an answer but couldn\'t find it anywhere. My question is reasonably simple: I have a background color of my body, then a large margin, and now I want a d

Answer 1

I needed something similar, and came up with using the :before (or :after) pseudoclasses:

#mydiv {
   background-color: #fbb;
   margin-top: 100px;
   position: relative;
}
#mydiv:before {
   content: "";
   background-color: #bfb;
   top: -100px;
   height: 100px;
   width: 100%;
   position: absolute;
}

JSFiddle