WordPress PWA Theme Options,Widgets + Menus with Tailwind

wp-nav_menu() add class on UL

<?php 
$args = array(
    'menu_class' => 'nav nav-tabs',        
    'menu' => '(your_menu_id)'
);
wp_nav_menu( $args ); 
?>

Add class on li using wp_nav_menu()

<?php
function add_classes_on_li($classes, $item, $args) {
  $classes[] = 'test_class';
  return $classes;
}
add_filter('nav_menu_css_class','add_classes_on_li',1,3);
?>

WordPress PWA Starter theme

WordPress Walker Class/Reference

CSS Dropdown Menu in WordPress

Tailwind Responsive Nav Menu