how to end pin on last section display

i need to pin false whenever last section are show See the Pen GRvqawW by gohilinfotech (@gohilinfotech) on CodePen

Ah sorry - typo! panel(s) - Here you go. See the Pen 143a7b54f938be3b1bae27700a6dcb1d by cassie-codes (@cassie-codes) on CodePen