split rows and nest to stack columns (#4129)

* split rows and nest to stack columns

* fix order

docs/tutorials/kubernetes-basics/index.html

@@ -40,6 +40,8 @@ title: Overview
 
     <div class="content__modules">
       <h2>Kubernetes Basics Modules</h2>
+      <div class="row">
+        <div class="col-md-12">
           <div class="row">
             <div class="col-md-4">
               <div class="thumbnail">
@@ -65,6 +67,10 @@ title: Overview
                 </div>
               </div>
             </div>
+          </div>
+        </div>
+        <div class="col-md-12">
+          <div class="row">
             <div class="col-md-4">
               <div class="thumbnail">
                 <a href="/docs/tutorials/kubernetes-basics/expose-intro/"><img src="./public/images/module_04.svg?v=1469803628347" alt=""></a>
@@ -91,6 +97,8 @@ title: Overview
             </div>
           </div>
         </div>
+      </div>
+    </div>
 
     <div class="row">
       <div class="col-md-12">