hi guys.im wondering how i can customize my website design.wich file of php contains divs and such of menu(i could find only php function on nav-menu.php and nav-menu-template.php)
it would beuseful to find the page with div, ul, li etc. of menu so i could change html classes and so to add my custom.
this make my second question:
on wich file i should add my custom css design cuz my theme have like 3 css files.