This would be easier to do with flexbox. Using flexbox will let you not to specify the height of your content and can adjust automatically on the height it contains.
here's the gist of the demo
.container{
display: flex;
height: 100%;
justify-content: center;
align-items: center;
}
html
<div class="container">
<div class='content'> //you can size this anyway you want
put anything you want here,
</div>
</div>