Small CSS FIX for maxi-menu - Joomla

Hi Freelancers, Looking for a simple CSS fix for one of my website.. I have a maximenu on my joomla 3.2 websites, the position of dropdown is right now fixed and full width hence it goes down on scroll.. Need a fix such that it doesnt go down on scroll and full width.. Please write "Maxi" to prove you are not spam... URL will be shared to selected freelancers... Happy bidding