set PageItemControl color for subnavigation

apps/app/src/components/Common/Dropdown/PageItemControl.tsx

@@ -335,7 +335,7 @@ export const PageItemControlSubstance = (props: PageItemControlSubstanceProps):
 
   return (
     <NotAvailableForGuest>
-      <Dropdown isOpen={isOpen} toggle={() => setIsOpen(!isOpen)} data-testid="open-page-item-control-btn">
+      <Dropdown isOpen={isOpen} toggle={() => setIsOpen(!isOpen)} className="grw-page-item-control" data-testid="open-page-item-control-btn">
         { children ?? (
           <DropdownToggle color="transparent" className="border-0 rounded btn-page-item-control d-flex align-items-center justify-content-center">
             <span className="material-symbols-outlined">more_vert</span>

apps/app/src/components/PageControls/PageControls.module.scss

@@ -1,3 +1,18 @@
+@use '@growi/core/scss/bootstrap/init' as bs;
+
+@use './button-styles';
+
+// PageItemControl styles
 .grw-page-controls :global {
+  .btn-page-item-control {
+    @extend %btn-basis;
+  }
+}
 
+// == Colors
+// PageItemControl colors
+.grw-page-controls :global {
+  .btn-page-item-control {
+    @include button-styles.btn-color(bs.$gray-500);
+  }
 }