"z-index" for columns

I have a strip with two columns. If I resize my browser so that the left column content overlaps the right column a little then the right column is always on top. I would essentially like to tell the left column to be “on top”, but I see no options for arranging the columns or even the content in the columns. Any suggestion?

You can’t do much with —> COLUMNS and COLUMNSTIPs…