Fixed the header/nav to the top of the page in a slightly different style via a class.
function scrolled_menu() {
if ($(window).scrollTop() > $('header').height()) {
$('header').addClass('fixed_type');
$('html').addClass('fixed_type_html');
} else {
$('header').removeClass('fixed_type');
$('html').removeClass('fixed_type_html');
}
}