background color about vue component

index.html

@@ -10,7 +10,7 @@
     <!-- <h3>this is node -> Vue test</h3> -->
     <div id='app'  style='color:red; font-size:20px; font-weight:bold;'>app node start...</div>
     <template id="my-app">
-		<header></header>
+		<header>default header component</header>
 		<!--<div v-html='info'></div> 
 		<Home @op="add">home vue</Home>
 		<h5 style="color:oranged">{{number}}</h5>