CSS code for dropdown-menu (transition)

Hi again,
I want to add the css code you used on BlackFyre for the dropdown-menu (I think this is the correct name) for add it to my navbar. I looked for everywhere and I can’t make it work yet -_-. I want to add a little transition like BlackFyre has.
And I’m looking a code for sticky menu (the wp plugin doesn’t work correctly, and I don’t want to add any plugin)
Do you know where can I find them?
Thank you so much!

Regards.