So far I have the three columns laid out in a vertical box (can't post images yet so here's a link): http://imgur.com/4Y34c

<div id="vbox">
<div id="blck1"></div>
<div id="blck2"></div>
<div id="blck3"><div id="yellow"></div><div id="blue"></div></div>
</div>

css

 #vbox{
 display: box;
 box-orient: vertical;
 }
 #vbox > div {
 box-flex: 1;
 }

The problem is that I don't know how to get the blue box to align to the bottom of the third column.. I tried all the alignment properties, i must be doing something wrong. Any ideas???