improve basic layout style (#884)

* improve basic layout style

* add missing modification

Author: kidonng

src/themes/basic/_layout.styl

@@ -120,6 +120,7 @@ li input[type='checkbox']
     margin 0 1rem
     padding 5px 0
     position relative
+    cursor pointer
 
     ul
       background-color #fff
@@ -277,8 +278,9 @@ main.hidden
   transition opacity 0.3s
   width $sidebar-width - 16px
   z-index 30
+  cursor pointer
 
-  .sidebar-toggle-button:hover
+  &:hover .sidebar-toggle-button
     opacity 0.4
 
   span