Need help to make the background of the "search with" box in the address bar transparent

https://preview.redd.it/qwj9ik78kzgf1.png?width=265&format=png&auto=webp&s=8707506d629edaf39e3824d2a073343536e53b14

I've tried everything I know, seems to be impossible from my perspective.
Please let me know if you have any ideas.