delete unnecessary code for nav tabs

src/client/styles/scss/theme/island.scss

@@ -92,13 +92,13 @@ html[dark] {
     }
   }
 
-  .nav-tabs,
-  .nav-tabs .nav-link.active,
-  .nav-link {
-    background: none;
-    border-color: $color-primary;
-    border-bottom-color: $color-primary;
-  }
+  // .nav-tabs,
+  // .nav-tabs .nav-link.active,
+  // .nav-link {
+  //   background: none;
+  //   border-color: $color-primary;
+  //   border-bottom-color: $color-primary;
+  // }
 
   .card,
   .card-header {