What is the simplest way to blur a UIDocument

I have a UI based on UI Toolkit where each panel is a UIDocument. Working great but I’m looking for a way to blur the background panel whenever I popup a smaller panel on top of it. Anyone have a simple solution for this?

Same issue here… CSS has some blur effects, but they seem to not have been implemented in USS. Wondering if there is a simple approach.

You would need to use a render texture.