Remove the two slashes in front of the justify-content value you want to test.

A
A
BBB
CCCCCC
A
BBB
CCCCCC
DD
EEEE
FFFFF
GGGGGGG
H
III
A
BBB
CCCCCC
DD
EEEE
FFFFF
GGGGGGG
H
III

justify-content: flex-start; ⤴