FlexBox align-content DEMO

flex-start

Child 1
Child 2
Child 3
Child 4

flex-end

Child 1
Child 2
Child 3
Child 4

center

Child 1
Child 2
Child 3
Child 4

space-between

Child 1
Child 2
Child 3
Child 4

space-around

Child 1
Child 2
Child 3
Child 4