Hmmm, a 3500+ line CSS file, and almost 400 lines of HTML, is a bit overwhelming for any unpaid forum enthusiast to delve in to in their free time. But, you can help increase your chance of help if you reduce the demo dramatically.
Go through the process of removing all the superfluous CSS (and HTML) until just the problem elements exist. You can do this by systematically removing small, logical blocks one-by-one while checking the results between changes. The live update nature of CodePen is great for this. When you identify the element that affects/creates the gap, look at its CSS in more detail. If you go through this cutting-down exercise, 9 times out of 10 you’ll fix the problem yourself.
Unfortunately, knowing how time consuming this process can be, especially in an unfamiliar codebase of this size, will put many folks off trying to help. On the other hand, if do most of the elimination work for us, the leaner, lighter demo will be much more inviting for potential helpers to look-over and fix.
