Drop-down menu customisation help

Hello,
I have created a drop-down for my primary menu. It looks great for mobile view, but for desktop view, it’s not looking good and background appears as blackish grey. And also, the line-height of the menu items is not properly set.
I was looking for the customized options, but did not get it.
Please help.
Waiting for your reply.

Thank you.
Aasher Singh.