Custom HTML not rendering properly responsive on mobile

Greetings:
I coded a coming soon page in a separate program, and embedded it in the custom area.

All looks great on desktop, and looks great even when I shrink the window to emulate a mobile sized screen.

However, when I view the site on Safari and Chrome in iPhone 6S, the site is simply scaled down and not stacking responsively.

Am I missing some setting? I’ve got it set now to responsive background and to be contained, but that doesn’t work. I’ve tried cover, that doesn’t work. I’ve tried unchecking responsive and so on….

Appreciate any advice….

The page I need help with: [log in to see the link]