I finally managed to edit the css of the Twenty Fourteen theme, to update the colours and layout as per my wish. I did it in the main stylesheet itself but would suggest you create a child theme and edit css there. It’s far more simpler as this theme was updated a couple of times and I lost the changes made when I had to update it.
This blog gives you the necessary CSS code to look for and edit or copy the code into you child theme css.
