WP Menu Item Count for Mobile Menu Transitions

menu-transitions.php

<?php
    // you can get the menu by name, ID, slug or location
	$menu_count = wp_get_nav_menu_object( 'Main Menu' ); // here we're grabbing it by name
	$menu_count = $menu_count->count
?>

<style type="text/css">

	<?php for($i = 1; $i <= $menu_count; $i++) { ?>

		<?php $delay = $i * 0.033; ?>
		
		#mobile-nav li:nth-of-type(<?php echo $i; ?>) {
			-webkit-transition-delay: <?php echo $delay; ?>s;
			-moz-transition-delay: <?php echo $delay; ?>s;
			-o-transition-delay: <?php echo $delay; ?>s;
			transition-delay: <?php echo $delay; ?>s;
		}

	<?php } ?>

</style>

output.php

<?php // assuming your menu count was four, this is what the CSS/PHP combo would output ?>

<style type="text/css">

	#mobile-nav li:nth-of-type(1) {
		-webkit-transition-delay: 0.033s;
		-moz-transition-delay: 0.033s;
		-o-transition-delay: 0.033s;
		transition-delay: 0.033s;
	}

	#mobile-nav li:nth-of-type(2) {
		-webkit-transition-delay: 0.066s;
		-moz-transition-delay: 0.066s;
		-o-transition-delay: 0.066s;
		transition-delay: 0.066s;
	}

	#mobile-nav li:nth-of-type(3) {
		-webkit-transition-delay: 0.099s;
		-moz-transition-delay: 0.099s;
		-o-transition-delay: 0.099s;
		transition-delay: 0.099s;
	}

	#mobile-nav li:nth-of-type(4) {
		-webkit-transition-delay: 0.132s;
		-moz-transition-delay: 0.132s;
		-o-transition-delay: 0.132s;
		transition-delay: 0.132s;
	}
	
</style>