How to change block color based on background color?

Question

JavaScript

How to make a txt block change color depending on the block in which it is located? using Intersection Observer API . Down everything works fine, but I can not achieve the same behavior when scrolling to the top https://jsfiddle.net/tkhpoa52/

Answer 1

Here is the solution turned out - https://jsfiddle.net/xyj2sver/2/
Suggest your options, it will be interesting to see