删掉部分多于代码，添加404页面，添加normalize.css

frontend/src/App.vue

@@ -4,7 +4,7 @@
     <router-link to="/">Home</router-link> |
     <router-link to="/about">About</router-link>
   </nav>
-  <router-view/>
+  <router-view />
 </template>
 
 <script>
@@ -25,12 +25,9 @@ export default {
 </script>
 
 <style>
+@import 'normalize.css/normalize.css';
+
 #app {
-  font-family: Avenir, Helvetica, Arial, sans-serif;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
   text-align: center;
-  color: #2c3e50;
-  margin-top: 60px;
 }
 </style>