CSS: Why background-color breaks/removes the box-shadow?

Question

I have a pretty simple div structure - tree boxes with middle box highlighted with box-shadow:

Answer 1

It has to do with the z-index of the items. Try adding this to your existing css:

.obOffer {
    position: relative;
    z-index: 10;
}

.obHiLight {
    position:relative;
    z-index: 100;
}​