Fix tabindex attribute breaking default text cursor in Firefox

views/app.erb

@@ -35,7 +35,7 @@
     </div>
   </section>
   <div class="_container" role="document">
-    <main class="_content _content-loading" role="main" tabindex="1"></main>
+    <main class="_content _content-loading" role="main"></main>
   </div>
 </div>
 <style data-size="<%= app_size %>" data-resizer>