Fix close sidebar in firefox

sass/courseware/_sidebar.scss

 section.course-index {
   @extend .sidebar;
-  position: relative;
   @extend .tran;
 
   div#open_close_accordion {
     @include box-shadow(0 1px 0 #eee);
     border-bottom: 1px solid #d3d3d3;
     padding: 0 lh();
+    position: relative;
 
     h2 {
       padding-right: 20px;
@@ -18,7 +18,7 @@ section.course-index {
       height: 16px;
       position: absolute;
       padding: 8px;
-      top: 12px;
+      top: -12px;
       right: -1px;
       border: 1px solid #D3D3D3;
       background: #eee url('/static/images/slide-left-icon.png') center center no-repeat;