sidebar disappears on responsive screen

I am using the hemingway theme and have added a few useful widgets to my sidebar column.

However, when viewing the site on a device with less than 800 px width, such as iPad or iPhone, the sidebar column is removed. This makes sense of course, but it also means the content of the sidebar is no longer displayed. In my case there is are some social links in the sidebar which indeed should be still available on a smart phone and indeed a link to a phone only social thing, it is more important to display on a phone than otherwise!

Where is this responsive bit coded, so I could have a look at making the sidebar display at the bottom of the page, perhaps below Footer C as it is on the widget setup page?

Or perhaps add yet another widget called ‘device footer’ which only turns on when the certain responsive settings?

Thanks all the same.