Fix theme consistency, i18n completeness, CSS variable naming, and hardcoded strings

src/app/admin/calendar/[id]/page.tsx

@@ -137,7 +137,7 @@ export default async function AdminCalendarCampaign({
           </thead>
           <tbody>
             {rewards.map((r) => (
-              <tr key={r.id} className="border-t border-[var(--border)]">
+              <tr key={r.id} className="border-t border-[var(--border-subtle)]">
                 <td>{r.id}</td>
                 <td>{r.productName || <span className="text-sm text-gray-500 dark:text-gray-400">—</span>}</td>
                 <td className="text-sm text-gray-500 dark:text-gray-400 whitespace-nowrap">{r.itemId > 0 ? r.itemId : "—"}</td>