no message

demo/route/src/components/header.jsx

@@ -18,11 +18,11 @@ class Header extends Component{
     }
     render(){
         return(
-            <div>
+            <div className="header">
                 <h1>React route演示案例</h1>
                 <button onClick={this.back}>前进</button>
                 <button onClick={this.forward}>后退</button>
-                <button onClick={this.go}>后退2</button>
+                <button onClick={this.go}>后退2步骤</button>
             </div>
         )
     }

demo/route/src/components/style.css

@@ -45,4 +45,9 @@
 }
 .home .homeContent{
     color: #333;
+}
+.header{
+    box-sizing: border-box;
+    padding-bottom: 12px;
+    border-bottom: 1px solid red;
 }