Testimonials in mobile display

Hi, I'm using the testimonial option in the Catch Response theme to create three columns of text on my homepage. See www.icap2050.org/proposal. They look nice on a regular computer display. However, in the mobile display the first to columns appear side-by-side and the third column appears beneath them. Is there a way to stack these vertically in the mobile display so the viewer sees the first, followed by the second, followed by the third as he scrolls down. Thanks, Todd