It's because even though you are correctly hiding the mobile content for desktop display (and vice versa), the "section" which is containing the mobile footer content, and all it's accompanying padding still exist and are being shown. You want to hide the whole section, rather than just the inner div you made. However, targeting specific sections is where i get fuzzy, squarespace doesn't make that super easy and it's what i'm currently struggling with in my own site. Hope that at least gets you a direction to in.