How can I make the area move not from the beginning of the screen, but from the element itself?

Question

css

I saw that there was such a question on animation . The answer was given by the user RAX7 . Regarding this question, I'm interested in the following: how can I make the area move (in mousemove) not from the beginning of the screen, but from the very block where the canvas ( code ) is located. Now it turns out that if we move the mouse outside the canvas block, then the points still move.

If anyone has free time, please take a look and indicate what needs to be changed.