Form layout question~~Please help [SOLVED]

Hello campers
Would someone help me to see what’s wrong with my text input form?
Why there is a huge space between the text input line and my button? Since I have used<span> and .input-group
I’ve tried to see if I miss anything but really can’t figure it out myself. =(
Thanks for the help in advance.

here is the link:

Just solved the problem after I posted it…
didn’t know form-control actually matter.