diff --git a/app/Http/Controllers/Admin/FeedbackController.php b/app/Http/Controllers/Admin/FeedbackController.php
index a91fc42..23f1b69 100644
--- a/app/Http/Controllers/Admin/FeedbackController.php
+++ b/app/Http/Controllers/Admin/FeedbackController.php
@@ -15,7 +15,9 @@
 
 class FeedbackController extends Controller
 {
-    public function __construct(private readonly FeedbackService $service) {}
+    public function __construct(
+        private readonly FeedbackService $service,
+    ) {}
 
     public function index(PaginatedRequest $request): Response
     {
diff --git a/app/Http/Controllers/Admin/Manage/CourseController.php b/app/Http/Controllers/Admin/Manage/CourseController.php
index 1bc5c12..69c3fc6 100644
--- a/app/Http/Controllers/Admin/Manage/CourseController.php
+++ b/app/Http/Controllers/Admin/Manage/CourseController.php
@@ -7,7 +7,7 @@
 use App\Http\Requests\PaginatedRequest;
 use App\Models\Course;
 use App\Services\Admin\Manage\CourseService;
-use App\Services\Admin\Users\DepartmentService;
+use App\Services\Admin\Master\DepartmentService;
 use Illuminate\Http\RedirectResponse;
 use Inertia\Inertia;
 use Inertia\Response;
diff --git a/app/Http/Controllers/Admin/Manage/MaterialController.php b/app/Http/Controllers/Admin/Manage/MaterialController.php
index 90969aa..f12a842 100644
--- a/app/Http/Controllers/Admin/Manage/MaterialController.php
+++ b/app/Http/Controllers/Admin/Manage/MaterialController.php
@@ -49,8 +49,6 @@ public function destroy(Material $material): RedirectResponse
     {
         $this->service->delete($material);
 
-        Inertia::flash('toast', ['type' => 'success', 'message' => 'Materi berhasil dihapus.']);
-
-        return back();
+        return Inertia::flash('toast', ['type' => 'success', 'message' => 'Materi berhasil dihapus.'])->back();
     }
 }
diff --git a/app/Http/Controllers/Admin/Manage/ScheduleController.php b/app/Http/Controllers/Admin/Manage/ScheduleController.php
index ab2f482..4d6a724 100644
--- a/app/Http/Controllers/Admin/Manage/ScheduleController.php
+++ b/app/Http/Controllers/Admin/Manage/ScheduleController.php
@@ -48,8 +48,6 @@ public function destroy(Schedule $schedule): RedirectResponse
     {
         $this->service->delete($schedule);
 
-        Inertia::flash('toast', ['type' => 'success', 'message' => 'Jadwal berhasil dihapus.']);
-
-        return back();
+        return Inertia::flash('toast', ['type' => 'success', 'message' => 'Jadwal berhasil dihapus.'])->back();
     }
 }
diff --git a/app/Http/Controllers/Admin/Manage/TuitionInvoiceController.php b/app/Http/Controllers/Admin/Manage/TuitionInvoiceController.php
index d38d696..776238c 100644
--- a/app/Http/Controllers/Admin/Manage/TuitionInvoiceController.php
+++ b/app/Http/Controllers/Admin/Manage/TuitionInvoiceController.php
@@ -52,8 +52,6 @@ public function destroy(TuitionInvoice $tuitionInvoice): RedirectResponse
     {
         $this->service->delete($tuitionInvoice);
 
-        Inertia::flash('toast', ['type' => 'success', 'message' => 'Tagihan berhasil dihapus.']);
-
-        return back();
+        return Inertia::flash('toast', ['type' => 'success', 'message' => 'Tagihan berhasil dihapus.'])->back();
     }
 }
diff --git a/app/Http/Controllers/Admin/Master/AcademicTermController.php b/app/Http/Controllers/Admin/Master/AcademicTermController.php
index 1af7822..88be15b 100644
--- a/app/Http/Controllers/Admin/Master/AcademicTermController.php
+++ b/app/Http/Controllers/Admin/Master/AcademicTermController.php
@@ -14,7 +14,7 @@
 class AcademicTermController extends Controller
 {
     public function __construct(
-        private readonly AcademicTermService $service
+        private readonly AcademicTermService $service,
     ) {}
 
     public function index(PaginatedRequest $request): Response
@@ -33,18 +33,18 @@ public function store(AcademicTermRequest $request): RedirectResponse
         return to_route('admin.master.academic-terms.index');
     }
 
-    public function update(AcademicTermRequest $request, AcademicTerm $AcademicTerm): RedirectResponse
+    public function update(AcademicTermRequest $request, AcademicTerm $academicTerm): RedirectResponse
     {
-        $this->service->update($AcademicTerm, $request->validated());
+        $this->service->update($academicTerm, $request->validated());
 
         Inertia::flash('toast', ['type' => 'success', 'message' => 'Periode akademik berhasil diperbarui.']);
 
         return to_route('admin.master.academic-terms.index');
     }
 
-    public function destroy(AcademicTerm $AcademicTerm): RedirectResponse
+    public function destroy(AcademicTerm $academicTerm): RedirectResponse
     {
-        $this->service->delete($AcademicTerm);
+        $this->service->delete($academicTerm);
 
         return Inertia::flash('toast', ['type' => 'success', 'message' => 'Periode akademik berhasil dihapus.'])->back();
     }
diff --git a/app/Http/Controllers/Admin/Master/DepartmentController.php b/app/Http/Controllers/Admin/Master/DepartmentController.php
index 6496271..19b12ab 100644
--- a/app/Http/Controllers/Admin/Master/DepartmentController.php
+++ b/app/Http/Controllers/Admin/Master/DepartmentController.php
@@ -14,7 +14,7 @@
 class DepartmentController extends Controller
 {
     public function __construct(
-        private readonly DepartmentService $service
+        private readonly DepartmentService $service,
     ) {}
 
     public function index(PaginatedRequest $request): Response
diff --git a/app/Http/Controllers/Admin/Settings/ProfileController.php b/app/Http/Controllers/Admin/Settings/ProfileController.php
index c57ab8a..33c6b20 100644
--- a/app/Http/Controllers/Admin/Settings/ProfileController.php
+++ b/app/Http/Controllers/Admin/Settings/ProfileController.php
@@ -15,9 +15,6 @@
 
 class ProfileController extends Controller
 {
-    /**
-     * Show the user's profile settings page.
-     */
     public function edit(Request $request): Response
     {
         $user = $request->user();
@@ -37,9 +34,6 @@ public function edit(Request $request): Response
         ]);
     }
 
-    /**
-     * Update the user's profile information.
-     */
     public function update(ProfileUpdateRequest $request): RedirectResponse
     {
         $user = $request->user();
@@ -61,9 +55,6 @@ public function update(ProfileUpdateRequest $request): RedirectResponse
         return to_route('admin.settings.profile.edit');
     }
 
-    /**
-     * Delete the user's profile.
-     */
     public function destroy(ProfileDeleteRequest $request): RedirectResponse
     {
         $user = $request->user();
diff --git a/app/Http/Controllers/Admin/Settings/SecurityController.php b/app/Http/Controllers/Admin/Settings/SecurityController.php
index de8acc8..9909e66 100644
--- a/app/Http/Controllers/Admin/Settings/SecurityController.php
+++ b/app/Http/Controllers/Admin/Settings/SecurityController.php
@@ -11,9 +11,6 @@
 
 class SecurityController extends Controller
 {
-    /**
-     * Show the user's security settings page.
-     */
     public function edit(): Response
     {
         return Inertia::render('admin/settings/security', [
@@ -21,17 +18,12 @@ public function edit(): Response
         ]);
     }
 
-    /**
-     * Update the user's password.
-     */
     public function update(PasswordUpdateRequest $request): RedirectResponse
     {
         $request->user()->update([
             'password' => $request->password,
         ]);
 
-        Inertia::flash('toast', ['type' => 'success', 'message' => 'Kata sandi berhasil diperbarui.']);
-
-        return back();
+        return Inertia::flash('toast', ['type' => 'success', 'message' => 'Kata sandi berhasil diperbarui.'])->back();
     }
 }
diff --git a/app/Http/Controllers/Admin/Users/AdministratorController.php b/app/Http/Controllers/Admin/Users/AdministratorController.php
index 99cf316..0818188 100644
--- a/app/Http/Controllers/Admin/Users/AdministratorController.php
+++ b/app/Http/Controllers/Admin/Users/AdministratorController.php
@@ -15,7 +15,7 @@
 class AdministratorController extends Controller
 {
     public function __construct(
-        protected AdministratorService $service,
+        private readonly AdministratorService $service,
     ) {}
 
     public function index(Request $request): Response
diff --git a/app/Http/Controllers/Admin/Users/LecturerController.php b/app/Http/Controllers/Admin/Users/LecturerController.php
index fb217f2..8c6c1a3 100644
--- a/app/Http/Controllers/Admin/Users/LecturerController.php
+++ b/app/Http/Controllers/Admin/Users/LecturerController.php
@@ -5,7 +5,7 @@
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Admin\Users\LecturerRequest;
 use App\Models\User;
-use App\Services\Admin\Users\DepartmentService;
+use App\Services\Admin\Master\DepartmentService;
 use App\Services\Admin\Users\LecturerService;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Http\Request;
@@ -15,8 +15,8 @@
 class LecturerController extends Controller
 {
     public function __construct(
-        protected LecturerService $service,
-        protected DepartmentService $departmentService,
+        private readonly LecturerService $service,
+        private readonly DepartmentService $departmentService,
     ) {}
 
     public function index(Request $request): Response
diff --git a/app/Http/Controllers/Admin/Users/StudentController.php b/app/Http/Controllers/Admin/Users/StudentController.php
index 7a915b5..a55b6e3 100644
--- a/app/Http/Controllers/Admin/Users/StudentController.php
+++ b/app/Http/Controllers/Admin/Users/StudentController.php
@@ -5,7 +5,7 @@
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Admin\Users\StudentRequest;
 use App\Models\User;
-use App\Services\Admin\Users\DepartmentService;
+use App\Services\Admin\Master\DepartmentService;
 use App\Services\Admin\Users\LecturerService;
 use App\Services\Admin\Users\StudentService;
 use Illuminate\Http\RedirectResponse;
@@ -16,9 +16,9 @@
 class StudentController extends Controller
 {
     public function __construct(
-        protected StudentService $service,
-        protected DepartmentService $departmentService,
-        protected LecturerService $lecturerService,
+        private readonly StudentService $service,
+        private readonly DepartmentService $departmentService,
+        private readonly LecturerService $lecturerService,
     ) {}
 
     public function index(Request $request): Response
diff --git a/app/Services/Admin/Users/DepartmentService.php b/app/Services/Admin/Users/DepartmentService.php
deleted file mode 100644
index 67cf55f..0000000
--- a/app/Services/Admin/Users/DepartmentService.php
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-namespace App\Services\Admin\Users;
-
-use App\Models\Department;
-use Illuminate\Support\Collection;
-
-class DepartmentService
-{
-    public function getAll(): Collection
-    {
-        return Department::select(['id', 'name'])->get();
-    }
-}
diff --git a/docs/code-style.md b/docs/code-style.md
new file mode 100644
index 0000000..2b4315a
--- /dev/null
+++ b/docs/code-style.md
@@ -0,0 +1,155 @@
+# Panduan Gaya Kode
+
+Dokumen ini mencatat konvensi penulisan kode di proyek ini, supaya kontributor
+(termasuk AI assistant) mengikuti pola yang sama dan tidak menulis ulang
+solusi yang sudah ada dengan cara berbeda-beda di tiap file.
+
+Setiap bagian punya status:
+
+- ✅ **Selesai** — sudah diterapkan di seluruh kode yang relevan.
+- 🚧 **Sebagian** — sudah ada polanya, tapi belum diterapkan di semua tempat.
+- 📝 **Rencana** — baru berupa kesepakatan, belum diterapkan.
+
+---
+
+## 1. Enum ✅
+
+**Aturan:** setiap backed enum (`enum X: string`) wajib pakai trait
+`App\Enums\Concerns\HasValues`. Jangan pernah menulis
+`array_values(X::cases())` atau `array_column(X::cases(), 'value')` secara
+manual — pakai `X::values()` (atau `X::options()` kalau butuh label untuk
+dropdown/select).
+
+```php
+// app/Enums/Concerns/HasValues.php
+trait HasValues
+{
+    public static function values(): array   // ['male', 'female']
+    public static function options(): array   // [{value: 'male', label: 'Laki-laki'}, ...]
+}
+```
+
+Struktur enum standar:
+
+```php
+enum Gender: string
+{
+    use HasValues;
+
+    case Male = 'male';
+    case Female = 'female';
+
+    public function label(): string
+    {
+        return match ($this) {
+            self::Male => 'Laki-laki',
+            self::Female => 'Perempuan',
+        };
+    }
+}
+```
+
+**Sebelum → Sesudah**
+
+```php
+// ❌ Jangan
+'gender' => ['required', 'string', Rule::in(array_values(Gender::cases()))],
+'type' => ['required', 'string', Rule::in(array_column(FeedbackType::cases(), 'value'))],
+
+// ✅ Pakai
+'gender' => ['required', 'string', Rule::in(Gender::values())],
+'type' => ['required', 'string', Rule::in(FeedbackType::values())],
+```
+
+Untuk data yang dikirim ke frontend (mis. isi `<Select>`), pakai `options()`
+alih-alih membangun array `{value, label}` manual dengan `array_map`:
+
+```php
+// ❌ Jangan
+'types' => array_map(fn (FeedbackType $type) => [
+    'value' => $type->value,
+    'label' => $type->label(),
+], FeedbackType::cases()),
+
+// ✅ Pakai
+'types' => FeedbackType::options(),
+```
+
+Enum baru **wajib** langsung pakai `use HasValues;` sejak awal dibuat, tidak
+perlu menunggu ada kebutuhan `values()`/`options()` baru ditambahkan.
+
+---
+
+## 2. Migration ✅
+
+**Aturan:** kolom `enum()` di migration wajib pakai `EnumClass::values()`,
+konsisten dengan aturan Enum di atas. Kolom `->default()` wajib pakai
+`EnumClass::Case->value` (string), bukan objek case-nya langsung.
+
+```php
+// ❌ Jangan
+$table->enum('status', array_values(StudentStatus::cases()))
+    ->nullable()
+    ->default(StudentStatus::Active); // objek enum, bukan string
+
+// ✅ Pakai
+$table->enum('status', StudentStatus::values())
+    ->nullable()
+    ->default(StudentStatus::Active->value);
+```
+
+---
+
+## 3. Bahasa UI ✅
+
+Seluruh teks yang tampil ke pengguna (label, judul halaman, pesan toast,
+placeholder, pesan error) ditulis dalam **Bahasa Indonesia**. Istilah teknis
+dan identifier kode tetap dalam bahasa aslinya (bahasa Inggris), tapi teks
+yang dibaca pengguna — termasuk teks di halaman auth/settings bawaan
+starter-kit yang aslinya berbahasa Inggris — harus diterjemahkan supaya
+konsisten dengan sisa aplikasi.
+
+---
+
+## 4. Struktur modul Admin ✅
+
+Semua fitur berada di bawah `/admin` — tidak ada lagi controller atau
+halaman yang menggantung di top-level `App\Http\Controllers` /
+`resources/js/pages/` di luar folder `admin/`. Setiap fitur admin baru
+(CRUD) mengikuti struktur namespace yang sama, di salah satu dari lima grup:
+
+| Grup               | Namespace Controller/Request            | Prefix route       |
+| ------------------ | --------------------------------------- | ------------------ |
+| Master data        | `Admin\Master`                          | `admin/master/*`   |
+| Data operasional   | `Admin\Manage`                          | `admin/manage/*`   |
+| Manajemen pengguna | `Admin\Users`                           | `admin/users/*`    |
+| Pengaturan akun    | `Admin\Settings`                        | `admin/settings/*` |
+| Resource mandiri   | `Admin` (langsung, tanpa sub-namespace) | `admin/<resource>` |
+
+"Resource mandiri" dipakai untuk fitur yang tidak cocok masuk ke 4 grup di
+atas — misalnya `Admin\FeedbackController` di `admin/feedback` (data
+personal milik user yang sedang login, bukan data akademik yang dikelola
+admin atas user lain).
+
+Nama route mengikuti pola `admin.<grup>.<resource>.<action>` (atau
+`admin.<resource>.<action>` untuk resource mandiri), dan file Wayfinder
+hasil generate mengikuti struktur folder yang sama di
+`resources/js/routes/admin/<grup>/<resource>/`.
+
+Halaman CRUD frontend memakai pola: `PageHeader` (judul + tombol Tambah) →
+`FormDialog` (Create/Edit) → `DataTable` + `columns.tsx` → `DeleteConfirmDialog`.
+
+---
+
+## 5. Wayfinder ✅
+
+Selalu jalankan generate dengan flag form variant, supaya `<Form
+{...Controller.method.form()}>` tidak error saat runtime:
+
+```bash
+php artisan wayfinder:generate --with-form
+```
+
+`vite.config.ts` sudah diset `wayfinder({ formVariants: true })` sehingga
+dev-server otomatis benar. Flag `--with-form` hanya wajib diingat kalau
+generate manual lewat CLI.