show navbar when scroll down.

gistfile1.txt

.navbar {
  position:fixed;
  top:0px;
  width:100%;
  height:75px;
  background-color:#fff;
  color: #FFFFFF;
  z-index:9999;
  display: none;
  border: none;
}

<script type="text/javascript">
(function($) {
    $(document).ready(function(){
        $(window).scroll(function(){
            if ($(this).scrollTop() > 200) {
                $('.navbar').fadeIn(500);
            } else {
                $('.navbar').fadeOut(500);
            }
        });
    });
})(jQuery);
</script>