How to create 50% width regions

I'm customizing the Scribe theme. I wish to add two side by side regions with text and a button. Right now I have done this using two text boxes side by side, then two buttons side by side - but in responsive view, the two text boxes are shown one after the other with both buttons appearing after the second one, which is not correct.

correct desktop view:
[text box] [text box]
[button] [button]

correct mobile view:
[text box]
[button]
[text box]
[button]

Actual mobile view:
[text box]
[text box]
[button]
[button]

So obviously the text box and button need to be in the same container. I assume this means a "region".

So, I created a new region (as described in this article https://premium.wpmudev.org/blog/upfront-regions/) below the region with my main content. I then tried to create two side by side regions by adding a region to the right of the existing region. This new region, however, can only ever be resized to about a third of the width of the content region.

Is it possible to have two regions side by side?