title: Center div in parent with only min-height, and child may without height & with relative position
body: <p>so I have a div which is min-height 100%; (100% of the screen or more). The child holds the content and needs to be centered vertically, but it might extend the parent to more than 100% of its size. This child is variable in height.</p>
  
  <p>So is there a way with only css(3) to do this?</p>