[MarketPress eCommerce] Menu all messed up

Please see the menu at makeupgrammar.com

On laptop when I resize the website, instead of getting compact, each item goes in a separate line and makes a very long vertical menu. Checked on Chrome, Win 10.

On mobile (checked on Android Samsung Note 8), it doesn't fit…the prroducts menu is open but half of it is cut out as menu is not wide enough. The sub-menu items go horizontally instead of indented in the next line making the menu too wide and hence the entire main menu gets cut off on the left side.