Divides the extra space evenly between children
and before and after the children.

Similar to MainAxisAlignment.spaceEvenly,
but reduces half of the space before the first
child and after the last child
to half of the width between the children.

Example: Modifying main axis alignment

The following example explicitly sets
  mainAxisAlignment to its default value,
  MainAxisAlignment.start.

1. Click the Run button.

2. Change MainAxisAlignment.start to
         MainAxisAlignment.end, and run again.

Tip:
  Before moving to the next section,
  change MainAxisAlignment.end to another value.

crossAxisAlignment property

Positions children near the start of the cross axis. (Top for Row, Left for Column)

Positions children near the end of the cross axis. (Bottom for Row, Right for Column)