The primary direction items are laid out (defined by flex-direction ).

The axis perpendicular to the main axis (e.g., if the main axis is a row, the cross axis is a column). 2. Essential Container Properties

These properties control the overall layout of the items from the parent level. Basic concepts of flexbox - CSS - MDN Web Docs

The model relies on two primary components: the and Flex Items . Flex Items: The direct children of that container. The Two Axes Layout behavior is determined by two perpendicular axes:

The CSS Flexible Box Layout, or , is a one-dimensional layout model designed to distribute space and align items within a container. Unlike traditional CSS layouts (block and inline), Flexbox is direction-agnostic and allows elements to "flex"—growing to fill unused space or shrinking to prevent overflow. 1. Core Architecture