Menu bar on mobile

Hi, I know that I can't do too much to change the way the menu bars render on mobile devices, but is there anyway to change how it says "Menu," and put "categories" or something instead? Also, I've been messing around with the menu bar a lot, and now even if I get the text to be centered vertically on my full desktop browser, on mobile, the word "Menu" (and the 3 lines indicating click here to see menu options) are being pushed to the top of the div and I'd like them centered too. Thanks.