Use @tag-default-bg for multiselect tags

components/select/style/index.less

@@ -298,7 +298,8 @@
     }
 
     .@{select-prefix-cls}-selection__choice {
-      background-color: #f3f3f3;
+      color: @tag-default-color;
+      background-color: @tag-default-bg;
       border-radius: 4px;
       cursor: default;
       float: left;

components/style/themes/default.less

@@ -299,6 +299,11 @@
 @table-padding-vertical: 16px;
 @table-padding-horizontal: 8px;
 
+// Tag
+// --
+@tag-default-bg: #f3f3f3;
+@tag-default-color: @text-color;
+
 // TimePicker
 // ---
 @time-picker-panel-column-width: 56px;

components/tag/style/index.less

@@ -3,9 +3,6 @@
 
 @tag-prefix-cls: ~"@{ant-prefix}-tag";
 
-@tag-default-bg: @background-color-base;
-@tag-default-color: @text-color;
-
 .@{tag-prefix-cls} {
   display: inline-block;
   line-height: 20px;