Tribute page: ordered list within different divs?

User story:

  • For ≥768px, each description must be flush with its matching thumbnail
  • For <768px, description should stack below its matching thumbnail
  • Descriptions should be in an ordered list

I’m having trouble fulfilling user story #3.

This was the closest solution SO had to offer, but list group items seem to only work within a same row.

My codepen: .

Any suggestions? Many thanks in advance.