Edit in JSFiddle

<div class="box">BOX</div>
<div class="box">BOX</div>
<div class="box">BOX</div>

.box {
    box-shadow: 0 0 3px #900;
    margin: 10px;
    padding: 10px;
    transition: box-shadow .5s;
}
.box:hover {
    box-shadow: 1px 1px 10px #fcc;
}