Main axis

The direction flex items flow in; justify-content works along it.

What is the main axis in Flexbox?

The main axis is the direction items flow in: across for a row, down for a column. justify-content works along it.

.row { display: flex; flex-direction: row; justify-content: space-between; }   /* main axis: left to right */

Level: Journeyman · More CSS terms at this level

Updated September 27, 2026