Modifying Main Menu

Is it possible to change the typography of the main menu? I would like to both make the main menu font larger and increase the spacing between menu options.

Also, how might I go about removing the outlined black box which surrounds the main menu, social icons, and site tagline?

My apologies if these questions have been asked/answered many times before. I attempted to search the customizr support forms for keywords such as “menu” and “main menu” via google site search
(Site: http://ww.wp.xz.cn/support/theme/customizr menu) but to no avail, am I doing something wrong or is there another way to specifically search the customizr support forms for preexisting topics?

Thanks in advance for your help!
Michael