reset bootstrap4/_variables.scss file

resource/styles/bootstrap4/_variables.scss

@@ -302,7 +302,7 @@ $grid-breakpoints: (
 // $table-active-bg:             $table-hover-bg !default;
 
 // $table-border-width:          $border-width !default;
- $table-border-color:          $red !default;
+// $table-border-color:          $gray-300 !default;
 
 // $table-head-bg:               $gray-200 !default;
 // $table-head-color:            $gray-700 !default;