Customize main menu, customize header

Hello,

2 questions. thanks in advance!

1) Is there CSS I can add in the theme customizer that will allow me to center the menu, and resize the font of the menu items?

2) 1) Is there CSS I can add in the theme customizer that will a) allow me to take out the short vertical lines outlining the bottom header area – perhaps it is the main menu area, and b) change the color of the horizontal top and bottom header outlines from gray to a color of my choice?

Any help is greatly appreciated!

The page I need help with: [log in to see the link]