Need help with UI Raindrop effect

Hey everyone, I currently have a UI raindrop system like used in many games.

But I saw this video pop up: https://www.youtube.com/watch?v=bUvzz5gtiYg

And it really made me wonder how he made the elements react to neon or colors.
It looks like it’s using just those rays but I don’t really know. Anyone got any clues?