White space on mobile for Portfolio space

48 minutes ago, Melchior said:

Only, in mobile view, the portfolio items show up on top of the footer (see screenshot 2)

You're not actually adjusting the white space, you're adjusting the height to a fixed (screen relative) value which doesn't work on mobile. Your easiest fix if you like how it looks is to wrap the code in a media query so it only applies to desktop, you can try this:

@media only screen and (min-width:768px) {
  //// REPLACE THIS LINE WITH YOUR CODE ////
}