Columns and fragmentation
The content of a multi-column layout is fragmented. It essentially behaves the same way as content behaves in paged media — such as when you print a webpage. When you turn your content into a multicol container it is fragmented into columns, and the content breaks to allow this to happen.
Ref: https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Multiple-column_Layout
Live web: https://gitthuma.github.io/multicol-fragmentation/