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

src/app/admin/calendar/page.tsx

@@ -83,7 +83,7 @@ export default async function AdminCalendar() {
       {campaigns.length === 0 ? (
         <div className="admin-empty">{t("noCampaigns")}</div>
       ) : (
-        <div className="grid cols-3">
+        <div className="grid grid-cols-1 gap-4 md:grid-cols-3">
           {campaigns.map((c) => {
             const enabled = c.enabled === "1";
             const count = rewardCounts.get(c.id) ?? 0;