Cart disappears on mobile view

So I'm using the Foster template for www.supermoonbeautyco.com, and the shopping cart is in the upper right corner on desktop view. It is also in the upper right on horizontal mobile view. 

However, when a mobile device is vertical (how most of my customers are shopping) the cart disappears completely in favor of the default condensed navigation menu. There is no where to access the shopping cart anywhere in mobile view, when vertical. 

Can anyone walk me through how to override this? I've searched every setting possible in my pages, styles, etc. And there's just nothing. This is wild to me that this is how the template itself is set up.

This is a 'bug' in the default configuration of the Foster template. Squarespace have set MOBILE: CART to Position: Hide in Site Styles, but you can change it so that it appears in the header.

Thank you so much! Found that in the options, and corrected it. I appreciate you so much. Do you also know if there is a way to get the header bigger in this template? I've maxed out the size slider in the Site Styles. It's appears especially tiny in mobile view.

The slider is just a guide. You can usually type in any size by clicking on the numbers beside the slider. If that doesn’t work for you, let me know.