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

@mixin vertical-align {
  position: relative;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  transform: translateY(-50%);
}

.element p {
  @include vertical-align;
}