Fix markup error

index.html

@@ -33,7 +33,7 @@
           <strong>Oh no!</strong> We cannot connect!
         </div>
         <div class="panel-group" id="accordion">
-          <div class="panel ">
+          <div class="panel">
             <div class="panel-heading">
               <h4 class="panel-title">
                 <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapseOne">
@@ -77,7 +77,7 @@
               </div>
             </div>
           </div>
-          <div class="panel ">
+          <div class="panel">
             <div class="panel-heading">
               <h4 class="panel-title">
                 <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo">
@@ -97,6 +97,7 @@
                 </div>
               </div>
             </div>
+          </div>
           <div class="panel ">
             <div class="panel-heading">
               <h4 class="panel-title">