@millions-army-64326 Migrating the CSS will bring over your CSS code, but as @witty-room-67787 said, it is possible that it won’t be applied. If that happens, we would love to take a closer look and see if we can make it work.
Having said that, I would recommend doing the switch after January 5, because we are in code freeze now and can’t deploy potential fixes. If you would like, I can remind you on January 5 to try it and we’ll then work together to make sure you’re smooth sailing.