Align Div at bottom on main Div

Question

I have two divs, one inside the other and I would like the small div to be aligned at the buttom of the main div.

Here\'s my code so far. Currently, the button is at

Answer 1

Please try this:

#b {
display: -webkit-inline-flex;
display: -moz-inline-flex;
display: inline-flex;

-webkit-flex-flow: row nowrap;
-moz-flex-flow: row nowrap;
flex-flow: row nowrap;

-webkit-align-items: flex-end;
-moz-align-items: flex-end;
align-items: flex-end;}

Here's a JSFiddle demo: http://jsfiddle.net/rudiedirkx/7FGKN/.