How to shorten width of a div on certain sides but not others, and remove white spaces?

Visit <http://ift.tt/2d7OnEm; to see the demo.
[white space][1]
[div that needs to match width of element above it][2]


[1]: http://ift.tt/2cuWH2U
[2]: http://ift.tt/2d7NQ54

I've tried changing the width of the div, but it's just not working. Please help me D: