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

VerticalAlign.css

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

// Less Mixin 
.vertical-align {
  position: relative;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
}

// Sass Placeholder Selector
%vertical-align {
  position: relative;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -moz-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
}