Backdrop filter for nav drop down

hi anyone able to figure out how to get a backdrop filter working on nav dropdowns? I saw multiple posts asking the same but no solution. Is this possible?

What exactly is a backdrop filter? Do you mean adding a filter on the dropdown list element? Which filter are you hoping to use?

Hi, here is a read-only link. When the drop-down menu drops down i want to blur the area behind the menu. currently it’s just transparent.