diff --git a/app.js b/app.js
index b1865ab..639c544 100644
--- a/app.js
+++ b/app.js
@@ -5,4 +5,12 @@ var app = new Vue({
     attachGreen: false,
     attachBlue: true
   },
+  computed:{
+    divClasses(){
+      return {
+        red: this.attachRed,
+        blue: !this.attachRed
+      }
+    }
+  }
 });
diff --git a/index.html b/index.html
index 583cc5e..2dc2acc 100644
--- a/index.html
+++ b/index.html
@@ -11,14 +11,8 @@
           @click="attachRed = !attachRed"
           :class="{red: attachRed}"
           ></div>
-      <div class="demo"
-          @click="attachGreen = !attachGreen"
-          :class="{green: attachGreen}"
-          ></div>
-      <div class="demo"
-          @click="attachBlue = !attachBlue"
-          :class="{blue: attachBlue}"
-          ></div>
+          <div class="demo" :class="divClasses"></div>
+          <div class="demo"></div>
     </div>
     <script src="app.js" charset="utf-8"></script>
   </body>