Vertical align center

If you want to align a div vertically center and you don’t know its height use the below code:

.element {
    position: relative;
    top: 50%;
    transform: translateY(-50%);
}

Note that you need to specify a height to its parent element!

ref:  http://zerosixthree.se/vertical-align-anything-with-just-3-lines-of-css/