fix arrow positioning for moz.

public/javascripts/app/templates/post-viewer/nav.handlebars

 <a href="#" class="nav-arrow left" id="forward">
-  <img src="/images/arrow-left.png" />
+  <div class="nav-arrow-inner">
+    <img src="/images/arrow-left.png" />
+  </div>
 </a>
 
 <a href="#" class="nav-arrow right" id="back">
-  <img src="/images/arrow-right.png" />
+  <div class="nav-arrow-inner">
+    <img src="/images/arrow-right.png" />
+  </div>
 </a>

public/javascripts/app/views/post-viewer/nav.js

@@ -23,7 +23,7 @@ app.views.PostViewerNav = app.views.Base.extend({
     if(evt) { evt.preventDefault(); }
     var link;
 
-    evt.target.tagName == "IMG" ? link = $(evt.target).closest("a") : link = $(evt.target)
+    evt.target.tagName != "A" ? link = $(evt.target).closest("a") : link = $(evt.target)
     app.router.navigate(link.attr("href").substring(1), true)
   }
 

public/stylesheets/sass/new-templates.scss

@@ -219,7 +219,8 @@ $light-grey: #999;
 .nav-arrow {
   @include opacity(0.8);
   @include transition(background-color, 0.3s);
-  @include center();
+
+  display: table;
 
   position: fixed;
   height: 100%;
@@ -228,6 +229,12 @@ $light-grey: #999;
   padding: 0 13px;
   background-color: rgba(0,0,0,0);
 
+  .nav-arrow-inner {
+    padding: 0; margin: 0;
+    display: table-cell;
+    vertical-align: middle;
+  }
+
   img {
     @include opacity(0.5);