refactor[ScrollBar]: use el-scrollbar (#90)

src/styles/index.scss

@@ -5,25 +5,44 @@
 @import './sidebar.scss';
 
 body {
+  height: 100%;
   -moz-osx-font-smoothing: grayscale;
   -webkit-font-smoothing: antialiased;
   text-rendering: optimizeLegibility;
   font-family: Helvetica Neue, Helvetica, PingFang SC, Hiragino Sans GB, Microsoft YaHei, Arial, sans-serif;
 }
 
+label {
+  font-weight: 700;
+}
+
 html {
+  height: 100%;
   box-sizing: border-box;
 }
 
+#app{
+  height: 100%;
+}
+
 *,
 *:before,
 *:after {
   box-sizing: inherit;
 }
 
+a,
+a:focus,
+a:hover {
+  cursor: pointer;
+  color: inherit;
+  outline: none;
+  text-decoration: none;
+}
+
 div:focus{
   outline: none;
-}
+ }
 
 a:focus,
 a:active {