[NSFW] Drop Down Menu Question

Hi,

I have a couple questions regarding my drop down menu.

[NSFW] https://www.starletsheet.com/

Right now the dropdown background is a bright white and I’m considering two options to change it:

1. Make the dropdowns semi transparent. I’ve seen posts where someone mentioned that you can upload a gif file. Where and how would I do that? What size?

2. What I really want, but cannot afford to pay a designer to do, would be to make the dropdowns look exactly or similar to the ones here..https://www.tomford.com/#/en
I’ve been told that it would be done in Jquery. Is it something that a relative novice such as myself could figure out?

Thanks in advance and happy holidays.