fixed:侧边索引android不居中

@@ -168,7 +168,10 @@
         list-style: none;
         text-align: center;
         width: 100%;
-
+        diplay: flex;
+        height: 24px;
+        margin-bottom: 8px;
+        align-items: center;
 
         a {
             color: #fff;
@@ -176,7 +179,6 @@
             display: inline-block;
             width: 24px;
             height: 24px;
-            line-height: 24px;
 
             &.zoom {
                  background-color: #000;