Column Stacking on Mobile Devices

Dev theme

Where: Two columns at top of homepage.

Desktop site has the text column on left, youtube video column on right.

My goal: On mobile devices the text column is at top, video column below. Similar to how default Bootstrap columns would order from desktop to mobile using col-md-6.

Live test site: https://armarm.onedealerhub.com/

Thank you in advance. I normally would commit the time to trying to figure this out myself, but this is for a non-profit org that is in a time crunch.