diff --git a/src/modules/settings/system-settings-screen.tsx b/src/modules/settings/system-settings-screen.tsx
index 064506e..f92c202 100644
--- a/src/modules/settings/system-settings-screen.tsx
+++ b/src/modules/settings/system-settings-screen.tsx
@@ -90,14 +90,26 @@ const FRONTEND_DRAFT_KEYS = [
   "playRulesHtmlNe",
 ] as const satisfies readonly (keyof RuntimeDraft)[];
 
-function isSectionDirty(
+function isSectionDirty<const K extends keyof RuntimeDraft>(
   draft: RuntimeDraft,
   saved: RuntimeDraft,
-  keys: readonly (keyof RuntimeDraft)[],
+  keys: readonly K[],
 ): boolean {
   return keys.some((key) => draft[key] !== saved[key]);
 }
 
+function applyDraftFields<const K extends keyof RuntimeDraft>(
+  base: RuntimeDraft,
+  source: RuntimeDraft,
+  keys: readonly K[],
+): RuntimeDraft {
+  const next = { ...base };
+  for (const key of keys) {
+    next[key] = source[key];
+  }
+  return next;
+}
+
 function SaveActions({
   dirty,
   loading,
@@ -240,14 +252,8 @@ export function SystemSettingsScreen() {
     setDraft((prev) => ({ ...prev, [field]: value }));
   };
 
-  const discardSection = (keys: readonly (keyof RuntimeDraft)[]) => {
-    setDraft((prev) => {
-      const next = { ...prev };
-      for (const key of keys) {
-        next[key] = saved[key];
-      }
-      return next;
-    });
+  const discardSection = <const K extends keyof RuntimeDraft>(keys: readonly K[]) => {
+    setDraft((prev) => applyDraftFields(prev, saved, keys));
   };
 
   const handleSaveRuntime = async () => {
@@ -295,13 +301,7 @@ export function SystemSettingsScreen() {
       await updateAdminSetting(DRAW_KEYS.AUTO_PAYOUT, draft.autoPayout);
       await updateAdminSetting(DRAW_KEYS.APPLY_REBATE_TO_PAYOUT, draft.applyRebateToPayout);
       toast.success(t("system.saveRuntimeSuccess", { ns: "config" }));
-      setSaved((prev) => {
-        const next = { ...prev };
-        for (const key of RUNTIME_DRAFT_KEYS) {
-          next[key] = draft[key];
-        }
-        return next;
-      });
+      setSaved((prev) => applyDraftFields(prev, draft, RUNTIME_DRAFT_KEYS));
     } catch (error) {
       toast.error(
         error instanceof LotteryApiBizError ? error.message : t("system.saveFailed", { ns: "config" }),
@@ -319,13 +319,7 @@ export function SystemSettingsScreen() {
       await updateAdminSetting(FRONTEND_KEYS.PLAY_RULES_HTML_NE, draft.playRulesHtmlNe);
       await updateAdminSetting(FRONTEND_KEYS.PLAY_RULES_HTML, draft.playRulesHtmlZh);
       toast.success(t("system.saveFrontendSuccess", { ns: "config" }));
-      setSaved((prev) => {
-        const next = { ...prev };
-        for (const key of FRONTEND_DRAFT_KEYS) {
-          next[key] = draft[key];
-        }
-        return next;
-      });
+      setSaved((prev) => applyDraftFields(prev, draft, FRONTEND_DRAFT_KEYS));
     } catch (error) {
       toast.error(
         error instanceof LotteryApiBizError ? error.message : t("system.saveFailed", { ns: "config" }),