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(function () {
		var nav = $('.js-nav'),
			navItem = nav.children();

		navItem.on('click', function (e) {
			e.preventDefault();
			var el = $(this).attr('href');
			$('html, body').animate({scrollTop: $(el).offset().top}, 2000);
			return false;
		});
	})();
	
	if need offset top - add - $(el).offset().top - 100}, 2000);