I'm designing a website that uses multiple columns. It looks fine on desktop, but when I switch to mobile and tablet, the columns always merge into one, and stack all of the content. Am I missing some setting to fix this, and maintain the multiple columns on smaller screens?
In many places, having it stack on smaller screen sizes makes sense, but in some I still need the multi column layout. For example, I'd like to use a vertical divider line just to the left of a text box in many places.

