Site responsive to [two_third] … [one_third_last]

Hi.

I use the pro vision and I’m trying to post something on a page in 2 columns. (2/3) and (1/3) sizes using short codes [two_third] … [one_third_last]

For example, when I use [one_half] … [one_half_last] short codes, 2 columns displays on desktop and on iphone it displays one after the other.

But when I view it from iPhone using the [two_third] … [one_third_last], the 2 columns does not display one after the other. It displays side by side as it displays on the desktop. Which is not good looking.

Would you be able to resolve this issue please.

Thanks, Guy