Problem with mobile menu and current menu item in normal menu

Hello,
Padhang theme is really good, but I have 2 problems.

1st problem – my menu in mobile version not responding on any actions, it’s showing only as white box with empty square + “MENU” inside (lost clickable image for show up menu items, I think. but I didn’t do any moves with source theme files). What should I do with that?
I really want to have my website responsible for the all types of devices, you know.

2nd – I know how to set some styles for primary menu, but I don’t know how I can set some styles for current opened menu item. Please, what’s the css tag for the active current menu item?

Please, help me. I really appreciate your feedbacks.

Thank you!