Last column input width of 100% overflows container with Blueprint CSS

How do I correct for an <input> t开发者_如何学Goag with a width: 100% in the last column of a Blueprint CSS layout extending over the right edge of the container?

I have tried applying a right margin to the last class but that pushes the column down to the next row.

The solution is to go Blueprint all the way and remove the width: 100% and use the span-x classes to control the width of the input elements.