style:refine css

src/styles/index.scss

@@ -51,6 +51,10 @@ a:hover {
   text-decoration: none;
 }
 
+div:focus{
+  outline: none;
+ }
+
 .fr {
   float: right;
 }

src/styles/sidebar.scss

-.app-wrapper {
+#app {
   // 主体区域
   .main-container {
     min-height: 100%;