Fix the navigation for mobile

The nav was still being floated and the borders looked awkward.
Also, I've hidden the login drop down and force mobile users to click
through to the login page.

src/Packagist/WebBundle/Resources/public/css/main.css

@@ -191,13 +191,18 @@ strong {
 }
 
 @media (max-width: 767px) {
-  .navbar .nav > li > a, .navbar .nav > .active > a, .navbar .nav > .nav-user > .nav-user-signin, .navbar .nav > .nav-user > section {
-    border-right: 1px solid rgba(118, 111, 107, 0.69);
-    border-bottom: 1px solid rgba(118, 111, 107, 0.69);
-  }
-  .navbar .nav > li:last-child > a {
-    border-bottom: 0;
-  }
+    .navbar .nav { float: none; }
+    .navbar .nav > li > a,
+    .navbar .nav > .active > a {
+        border-bottom: 1px solid rgba(118, 111, 107, 0.69);
+    }
+    .navbar .nav > li:last-child > a {
+        border-bottom: 0;
+    }
+    .navbar .nav > .nav-user > .nav-user-signin:hover > .nav-user-menu,
+    .navbar .nav > .nav-user > .nav-user-signin:hover > .signin-box {
+        display: none;
+    }
 }
 
 .navbar .nav > .nav-user > section a {