So basically the problem here is that the animation opacity:1 will work out if it's on the first section but if its on second or other than first section..   It will not show the animation opacity:1 in the middle of its on section, You can see in my codepen.   Everything works out but if I added a new section on its top. It will not animated. Anyone can help me about this? Thank you. You can test it. Try to remove the first section and add it again and you will see the diffe