A tricky CSS selector question, don't know if it's even possible. 

Lets say this is the HTML layout: 

```
<div></div>
<div></div>  
<div></div>  
<div style="display:none"></div>
<div style="display:none"></div>  

```

I want to select the last `div`, which is displayed (ie. not `display:none`) which would be the third `div` in the given example.
Mind you, the number of `div`s on the real page can differ (even the `display:none` ones).