Breakpoint

A screen‑width threshold where design rules change (e.g., stack columns, swap visibility, adjust spacing).

Orientation

Row (horizontal) vs. stack (vertical) arrangement of child blocks.

Justification / Vertical Alignment

How children spread across the main axis (justification) and cross axis (vertical alignment).

Stack on Mobile

A common pattern that collapses columns into a single column at small widths. BBE makes the breakpoint and order fully controllable.