[Nexus]

function handler(event) {
    var hash = typeof event === 'string' ? event : event.target.hash;
    var headerHeight = $('.top').height();

    if (!hash)
        return


    var tag = $(hash);

    if (tag.length) {
        var offset = tag.offset().top - headerHeight;
        $('html, body').stop().animate({
            scrollTop: offset
        }, 2000);
    }

}

$('.top-menu a').on("click", handler);
$(function() {
    handler(location.hash);
});