I am wondering how can I set line-height to be always equal to height of the container div - in order to center the element inside of the container in the middle of the height of the container.

Lets say I have a following:

```
<div style="height:12%">
<i style="line-height:??"></i>
</div>

```

How can I set line height, so that it changes with the changes when the height of the container div changes?

Thanks   
uksz