Google Allo Style Compose Message Area

I am trying to create Google Allo style Compose message chat area in html and css and i looked at allo.google.com/web their web version of allo and i created mine here but the problem i am facing is my text area is scrolling horizontally beyond my container div and i couldn't figure it out whats causing it.I already tried adusting the width but its not the kind of solution i am looking for.

You guys can login to http://ift.tt/2u6K2KZ and see their send message area inside the chat screen. I am tru=ying to replicate that exactly.

Thanks.