Add Mix Blend Mode: Difference to Scrolling text block

Hello,

I am looking to add the mix-blend-mode: Difference to a scrolling text block but all the codes I have seen online in the forums don't work.  I have tried copying the block information using the chrome extension and using the tag .marquee h1 and still nothing works for the blend mode. I am able to change the color of the text but I am not seeing the difference effect applied.

In short, I would like my text that sits above an image or video to move across the image with the difference blend mode applied.

I would also like to add the difference blend mode to the hamburger menu.

Lastly, I will note this is not a global update but specific to 1 page

Thanks!