Convert admin pages to new Tailwind design pattern

- Replace 'card' class with 'admin-card' (gradient cards, dark mode support)
- Replace 'muted' class with consistent Tailwind muted states
- Standardize page headers with gradient backgrounds and Lucide icons
- Convert all inline styles to Tailwind classes
- Add admin-page CSS helpers (admin-card, admin-filter-bar, admin-section-title)
- Apply pattern to all 42 admin pages (was only 6 before)
- Zero TypeScript errors, production builds successfully

Co-authored-by: openhands <[email protected]>

src/app/admin/subscriptions/page.tsx

@@ -1,3 +1,4 @@
+import { CreditCard } from "lucide-react";
 import { StatusCard } from "@/components/admin/dashboard";
 import { prisma } from "@/lib/prisma";
 
@@ -47,10 +48,15 @@ export default async function AdminSubscriptions() {
 
   return (
     <main>
-      <h1>Subscriptions</h1>
-      <p className="muted" style={{ marginTop: "-0.4rem" }}>
-        Active Habbo Club / VIP subscriptions (expiry &gt; now). Read-only.
-      </p>
+      <div className="flex items-center gap-3 mb-6">
+        <div className="w-10 h-10 rounded-xl bg-gradient-to-br from-[var(--color-primary)]/20 to-[var(--color-primary)]/5 grid place-items-center">
+          <CreditCard size={20} className="text-[var(--color-primary)]" />
+        </div>
+        <div>
+          <h1 className="m-0 text-xl font-extrabold text-[var(--color-text)]">Subscriptions</h1>
+          <p className="m-0 text-xs text-[var(--color-text-muted)] mt-0.5">Active Habbo Club / VIP subscriptions (expiry &gt; now). Read-only.</p>
+        </div>
+      </div>
 
       <div className="grid grid-cols-[repeat(auto-fit,minmax(180px,1fr))] gap-3.5 mb-6">
         <StatusCard label="Active subs" value={active.length} icon="⭐" />
@@ -64,8 +70,8 @@ export default async function AdminSubscriptions() {
       </div>
 
       <section className="mt-6">
-        <h2>Active subscriptions ({active.length})</h2>
-        <div className="card">
+        <h2 className="admin-section-title">Active subscriptions ({active.length})</h2>
+        <div className="admin-card">
           <table>
             <thead>
               <tr>
@@ -81,7 +87,7 @@ export default async function AdminSubscriptions() {
                 const soon = s.expiresAt <= soonCutoff;
                 return (
                   <tr key={s.id}>
-                    <td className="muted">{s.id}</td>
+                    <td className="text-sm text-gray-500 dark:text-gray-400 whitespace-nowrap">{s.id}</td>
                     <td>{s.userId ?? "—"}</td>
                     <td>{s.subscriptionType ?? "—"}</td>
                     <td>
@@ -89,13 +95,13 @@ export default async function AdminSubscriptions() {
                         {soon ? "Expiring" : "Active"}
                       </span>
                     </td>
-                    <td className="muted">{fmt(s.expiresAt)}</td>
+                    <td className="text-sm text-gray-500 dark:text-gray-400 whitespace-nowrap">{fmt(s.expiresAt)}</td>
                   </tr>
                 );
               })}
             </tbody>
           </table>
-          {active.length === 0 ? <p className="muted">No active subscriptions.</p> : null}
+          {active.length === 0 ? <div className="admin-empty">No active subscriptions.</div> : null}
         </div>
       </section>
     </main>