Where can i adjust the width of sys_main_logo ?

Where can i adjust the width of sys_main_logo ?  (div.sys_main_menu) or (div.sys_mm)

I want to change the width of the top menu and the above logo section.

I found several places of sys_main_logo but i cant find the right position (in code or in admin section) where i can adjust the value for width.

Download Chrome browser and check inside the Element Inspector, it will show you exact file and exact place where you have to change it.