With flexbox, you won’t need those selectors: you can accomplish the same effect by adding display: flex to the container.
When you add this property to the container, you’re telling that element, “Hey buddy, you’re in charge here! Lay out your direct descendant children according to flexbox rules.” In their most basic form, these rules arrange the children along what’s called the “main axis”, by default the x–axis, from left to right.
