Centering Percentage Width/Height Elements
/* http://css-tricks.com/centering-percentage-widthheight-elements */
.center {
position: absolute;
left: 50%;
top: 50%;
/*
Nope =(
margin-left: -25%;
margin-top: -25%;
*/
/*
Yep!
*/
transform: translate(-50%, -50%);
/*
Not even necessary really.
e.g. Height could be left out!
*/
width: 40%;
height: 50%;
}