Navbar open/close moves the page to the top

[rom1v]

Since commit f039ccb (found through git bisect), opening/closing the navbar moves the page to the top, which is very annoying.

Reverting a part of the patch avoids the problem:

diff --git a/public/css/lanyon.css b/public/css/lanyon.css
index bc1408f..50bd789 100644
--- a/public/css/lanyon.css
+++ b/public/css/lanyon.css
@@ -202,6 +202,7 @@ a.sidebar-nav-item:focus {
 
 /* Hide the sidebar checkbox that we toggle with `.sidebar-toggle` */
 .sidebar-checkbox {
+  display: none;
   position: absolute;
   opacity: 0;
   -webkit-user-select: none;

cc @mdo

[mdo]

Duplicate of #137.