How to Change Fonts and Sizes for the Header

Hello, I have few questions to ask. The site is MyHappyChoice.com 1) I am trying to change the font type and sizes for both English and Chinese for the new post header. 2) How to change fonts and sizes for the menu? 3) Can you recommend the Chinese fonts plugins? 4) How to remove the space on the right-hand side of the menu. Thank you very much.