Menu Customization-from another theme?

Just a question for anyone who comes across this before I figure it out myself.

So I just got my site up and running, and lately I am messing around with the theme and learning how to write some code. This is my first website- I have successfully modified the F8-lite theme through various experiments with the css and php.- Simple stuff.- (you can compare my site now, with the original F8-Lite theme’s demo page, which is at graphpaperpress themes)

I am now trying to tweak the menus apperance. – I like the placement of the menus, and that they are functioning as drop downs.- However I would like a cleaner look to them. The background, highlight effect, and shape are unsightly and I would rather have a rounded style like in the workaholic theme.-
Here is a friend of mine’s site. -He used the theme, and I think a friend of his built the site.- He’s pretty busy so I don’t wanna bug him about it.- the site is https://mpedro.com

I like the way the round edges encapsulate his drop menus.- I would like mine at https://beforecompletion.com to have the same look.-

I have looked at the code, but I am a noob and I don’t understand, even with firebug, what I should do to emulate this look.

Anyone have the solution at their fingertips due to their code genius. Thanks for the time!