Added nav bar and improved card look

static/js/core.js

@@ -1,4 +1,43 @@
 
+// Hide Header on on scroll down
+var didScroll;
+var lastScrollTop = 0;
+var delta = 5;
+var navbarHeight = $('nav-bar').outerHeight();
+
+$(window).scroll(function(event){
+    didScroll = true;
+});
+
+setInterval(function() {
+    if (didScroll) {
+        hasScrolled();
+        didScroll = false;
+    }
+}, 250);
+
+function hasScrolled() {
+    var st = $(this).scrollTop();
+    
+    // Make sure they scroll more than delta
+    if(Math.abs(lastScrollTop - st) <= delta)
+        return;
+    
+    // If they scrolled down and are past the navbar, add class .nav-up.
+    // This is necessary so you never see what is "behind" the navbar.
+    if (st > lastScrollTop && st > navbarHeight){
+        // Scroll Down
+        $('nav').addClass('nav-bar-up');
+    } else {
+        // Scroll Up
+        if(st + $(window).height() < $(document).height()) {
+            $('nav').removeClass('nav-bar-up');
+        }
+    }
+    
+    lastScrollTop = st;
+}
+
 function cardPressed() {
     this.classList.add('card-link-wrapper-active');
 }