@microace27095 and @board1774168228 I think Codecademy did this by accident. You can report this lesson (which I’ll also do) so that the curriculum developers can fix it
.child class displays the element as a block level flex container which takes the full width of its parent container. Content is centered based on the width of its parents container. Items are centered from to to bottom.
It centres the content of each child (in this case the text “Child 1” etc).
It’s not noticeable because the text is already filling up the space inside the container, so it’s already appears centred. But if you edit the text leaving just 1,2,3 respectively or if you increase the size of the container, you will notice a difference.