wordpress site plugin and customization

There are 2 requirements here - 1. I designed a website using Karma wordpress template([login to view URL]) and running into some issues in terms of visibility on different screen size monitors. Some monitors will show 3/4 of the page while others will only show 1/2 and user need to scroll down. I want the website to auto. adjust to the screens resolution/size so it shows same content no matter what monitor or laptop you look at. I have heard that it can be done in css quite easily. On the other hand I heard that the template I am using is fixed layout so it can't be done. So I am looking for some feedback on this. 2. I am using omni secure files plugin developed my omni logic for file sharing on the backend ([login to view URL]). I need some customization to it. I want to restrict the visibilty of certain files to certain users. Also, I want to make file sharing more secure. I am open to suggestions on this. Let me know if you need more information.