How to center div vertically inside of absolutely positioned parent div

Question

I am trying to get blue container in the middle of pink one, however seems vertical-align: middle; doesn\'t do the job in that case.

Answer 1

An additional simple solution

HTML:

    

        Text
    

---

CSS:

#d1{
    position:absolute;
    top:100px;left:100px;
}

#d2{
    border:1px solid black;
    height:50px; width:50px;
    display:table-cell;
    vertical-align:middle;
    text-align:center;  
}