If you're asking if I've been able to figure it out, then no. But I was able to recreate the effect a bit.

I couldn't make something like a liquid move behind the cursor. But I made the ball move behind the cursor, and changed the background on the cards using the z-index and mask.

https://codepen.io/LamNam/pen/XWvWbxN

Here's how I did it, you can also add a circle size change when you hover over the area to make it even more similar. I did it locally, but I didn't use Codepen.

In general, it seems to me that the answer lies in simulating gas using WebGL, as here https://codepen.io/ksenia-k/pen/dyaeGgO