(function main() {
	var active = $('ul.nav li.active');

	$('#ART').add('#credits').show(900);

	$('ul.nav').on('click', 'li', function() {
		$(active.removeClass('active')
		        .find('a')
		        .attr('href')).hide(300);
		$((active = $(this)).addClass('active')
		                    .find('a')
		                    .attr('href')).show(600);
	});
})();
@@ -77,20 +77,22 @@
 edits').
-show
+fadeIn
 (900);%0A%0A
@@ -218,12 +218,15 @@
 ')).
-hide
+fadeOut
 (300
@@ -344,14 +344,17 @@
 ')).
-show(6
+fadeIn(18
 00);

Use fadeIn/Out instead of show/hide since the latter are laggy in weaker machines