diff --git a/app/Filament/Resources/Learning/Assignments/Actions/MarkAsSentAction.php b/app/Filament/Resources/Learning/Assignments/Actions/MarkAsSentAction.php
new file mode 100644
index 0000000..7001077
--- /dev/null
+++ b/app/Filament/Resources/Learning/Assignments/Actions/MarkAsSentAction.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace App\Filament\Resources\Learning\Assignments\Actions;
+
+use App\Filament\Support\SystemNotification;
+use App\Models\Assignment;
+use Filament\Actions\Action;
+
+class MarkAsSentAction extends Action
+{
+    public static function getDefaultName(): ?string
+    {
+        return 'markAsSentAction';
+    }
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->label(function (array $arguments, ?Assignment $record) {
+            $assignment = $record ?? Assignment::find($arguments['record'] ?? null);
+
+            return $assignment?->is_sent_to_lecturer ? 'Buka Kunci' : 'Tandai Terkirim';
+        })
+            ->icon(function (array $arguments, ?Assignment $record) {
+                $assignment = $record ?? Assignment::find($arguments['record'] ?? null);
+
+                return $assignment?->is_sent_to_lecturer ? 'heroicon-o-lock-open' : 'heroicon-o-check-circle';
+            })
+            ->color(function (array $arguments, ?Assignment $record) {
+                $assignment = $record ?? Assignment::find($arguments['record'] ?? null);
+
+                return $assignment?->is_sent_to_lecturer ? 'warning' : 'success';
+            })
+            ->link()
+            ->visible(fn () => auth()->user()->hasRole(['Kosma', 'Developer']))
+            ->action(function (array $arguments, $livewire, ?Assignment $record) {
+                $assignment = $record ?? Assignment::find($arguments['record'] ?? null);
+                if (! $assignment) {
+                    return;
+                }
+
+                $assignment->update([
+                    'is_sent_to_lecturer' => ! $assignment->is_sent_to_lecturer,
+                ]);
+
+                SystemNotification::send($assignment->is_sent_to_lecturer ? 'assignment_sent' : 'assignment_unlocked')
+                    ->send();
+
+                if (isset($livewire->assignments)) {
+                    unset($livewire->assignments);
+                }
+            });
+    }
+}
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php b/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
index e4da826..bf35372 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/ListAssignments.php
@@ -7,6 +7,7 @@
 use App\Filament\Resources\Learning\Assignments\Actions\CreateAssignmentAction;
 use App\Filament\Resources\Learning\Assignments\Actions\DeleteAssignmentAction;
 use App\Filament\Resources\Learning\Assignments\Actions\EditAssignmentAction;
+use App\Filament\Resources\Learning\Assignments\Actions\MarkAsSentAction;
 use App\Filament\Resources\Learning\Assignments\Actions\PinAction;
 use App\Filament\Resources\Learning\Assignments\Actions\ShareAssignmentAction;
 use App\Filament\Resources\Learning\Assignments\AssignmentResource;
@@ -156,6 +157,11 @@ public function shareAssignmentAction(): Action
         return ShareAssignmentAction::make();
     }
 
+    public function markAsSentAction(): Action
+    {
+        return MarkAsSentAction::make();
+    }
+
     #[Computed]
     public function assignments(): Collection
     {
@@ -234,15 +240,20 @@ public function assignments(): Collection
 
     private function getAssignmentPriority($assignment): int
     {
+        $isSent = $assignment->is_sent_to_lecturer;
+        if ($isSent) {
+            return 5; // Closed
+        }
+
         $isSubmitted = $assignment->assignmentSubmissions?->isNotEmpty();
         $isOverdue = now()->isAfter($assignment->due_date);
 
         if (! $isOverdue) {
-            return $isSubmitted ? 2 : 1;
+            return $isSubmitted ? 3 : 1; // 1: Active, 3: Completed Active
         }
 
-        // Overdue
-        return $isSubmitted ? 3 : 4;
+        // Overdue but not sent
+        return $isSubmitted ? 4 : 2; // 2: Actionable Overdue, 4: Completed Overdue
     }
 
     #[Computed]
@@ -269,8 +280,10 @@ public function assignmentCards()
                 $isLeader = $userGroup && $userGroup->leader_id === $studentProfile->id;
             }
 
+            $isSentToLecturer = $assignment->is_sent_to_lecturer;
             $isOverdue = now()->isAfter($assignment->due_date);
-            $canSubmit = ! $isOverdue;
+
+            $canSubmit = ! $isSentToLecturer;
 
             $canSubmitByRole = ! $isGroup || $isLeader;
             $canSubmitActual = $canSubmit && $canSubmitByRole;
@@ -279,30 +292,35 @@ public function assignmentCards()
             $isNew = $assignment->created_at?->diffInDays(now()) <= 3;
             $isPinned = in_array($assignment->id, $pinnedIds);
 
-            $statusLabel = SystemNotification::getByKey('labels.assignment_status.not_submitted');
-            $statusColor = 'warning';
-            $statusIcon = 'heroicon-o-arrow-up-tray';
-
             if ($isSubmitted) {
-                $statusLabel = SystemNotification::getByKey('labels.assignment_status.submitted');
-                $statusColor = 'success';
-                $statusIcon = 'heroicon-o-check-circle';
+                $submissionLabel = SystemNotification::getByKey('labels.assignment_status.submitted');
+                $submissionColor = 'success';
+                $submissionIcon = 'heroicon-o-check-circle';
             } elseif ($isOverdue) {
-                $statusLabel = SystemNotification::getByKey('labels.assignment_status.overdue');
-                $statusColor = 'danger';
-                $statusIcon = 'heroicon-o-clock';
+                $submissionLabel = SystemNotification::getByKey('labels.assignment_status.overdue');
+                $submissionColor = 'danger';
+                $submissionIcon = 'heroicon-o-clock';
             } elseif ($isGroup && ! $isLeader && ! $isSubmitted) {
-                $statusLabel = SystemNotification::getByKey('labels.assignment_status.waiting_leader');
-                $statusColor = 'gray';
-                $statusIcon = 'heroicon-o-user-group';
+                $submissionLabel = SystemNotification::getByKey('labels.assignment_status.waiting_leader');
+                $submissionColor = 'gray';
+                $submissionIcon = 'heroicon-o-user-group';
+            } else {
+                $submissionLabel = SystemNotification::getByKey('labels.assignment_status.not_submitted');
+                $submissionColor = 'warning';
+                $submissionIcon = 'heroicon-o-arrow-up-tray';
             }
 
+            $deliveryLabel = $isSentToLecturer ? 'Telah Dikirim' : 'Belum Dikirim';
+            $deliveryColor = $isSentToLecturer ? 'success' : 'amber';
+            $deliveryIcon = $isSentToLecturer ? 'heroicon-o-check-badge' : 'heroicon-o-clock';
+
             return (object) [
                 'id' => $assignment->id,
                 'title' => $assignment->title,
                 'course_name' => $assignment->course?->name ?? '-',
                 'due_date_formatted' => $assignment->due_date?->translatedFormat('l, d F Y H:i'),
                 'submitted_at_formatted' => ($isSubmitted && $submission->submitted_at) ? $submission->submitted_at?->translatedFormat('l, d F Y H:i') : null,
+                'is_sent_to_lecturer' => $isSentToLecturer,
                 'is_submitted' => $isSubmitted,
                 'is_group' => $isGroup,
                 'is_leader' => $isLeader,
@@ -311,8 +329,28 @@ public function assignmentCards()
                 'is_urgent' => $isUrgent,
                 'is_new' => $isNew,
                 'is_pinned' => $isPinned,
-                'status_label' => $statusLabel,
-                'status_icon' => $statusIcon,
+                'submission_status' => (object) [
+                    'label' => $submissionLabel,
+                    'color' => $submissionColor,
+                    'icon' => $submissionIcon,
+                    'classes' => Arr::toCssClasses([
+                        'inline-flex items-center gap-1 rounded-full px-2.5 py-0.5 text-xs font-semibold', // font-semibold for clarity
+                        'bg-success-100 text-success-700 dark:bg-success-900/30 dark:text-success-400' => $submissionColor === 'success',
+                        'bg-danger-100 text-danger-700 dark:bg-danger-900/30 dark:text-danger-400' => $submissionColor === 'danger',
+                        'bg-warning-100 text-warning-700 dark:bg-warning-900/30 dark:text-warning-400' => $submissionColor === 'warning',
+                        'bg-gray-100 text-gray-500 dark:bg-gray-800 dark:text-gray-400' => $submissionColor === 'gray',
+                    ]),
+                ],
+                'delivery_status' => (object) [
+                    'label' => $deliveryLabel,
+                    'color' => $deliveryColor,
+                    'icon' => $deliveryIcon,
+                    'classes' => Arr::toCssClasses([
+                        'inline-flex items-center gap-1 rounded-full px-2.5 py-0.5 text-xs font-bold ring-1 ring-inset', // font-bold and ring for "delivery" status to make it pop
+                        'bg-success-50 text-success-700 ring-success-600/20 dark:bg-success-900/10 dark:text-success-400 dark:ring-success-500/20' => $deliveryColor === 'success',
+                        'bg-amber-50 text-amber-700 ring-amber-600/20 dark:bg-amber-900/10 dark:text-amber-400 dark:ring-amber-500/20' => $deliveryColor === 'amber',
+                    ]),
+                ],
                 'url' => AssignmentResource::getUrl('submit', ['record' => $assignment->id]),
                 // Pre-calculated classes
                 'card_classes' => Arr::toCssClasses([
@@ -327,14 +365,6 @@ public function assignmentCards()
                     'bg-danger-50 dark:bg-danger-900/20 text-danger-600 dark:text-danger-400' => ! $isSubmitted && $isOverdue,
                     'bg-warning-50 dark:bg-warning-900/20 text-warning-600 dark:text-warning-400' => ! $isSubmitted && ! $isOverdue,
                 ]),
-                'status_badge_classes' => Arr::toCssClasses([
-                    'inline-flex items-center gap-1 rounded-full px-2.5 py-0.5 text-xs font-medium',
-                    'bg-amber-100 text-amber-700 dark:bg-amber-900/30 dark:text-amber-400' => $statusColor === 'amber',
-                    'bg-success-100 text-success-700 dark:bg-success-900/30 dark:text-success-400' => $statusColor === 'success',
-                    'bg-danger-100 text-danger-700 dark:bg-danger-900/30 dark:text-danger-400' => $statusColor === 'danger',
-                    'bg-warning-100 text-warning-700 dark:bg-warning-900/30 dark:text-warning-400' => $statusColor === 'warning',
-                    'bg-gray-100 text-gray-500 dark:bg-gray-800 dark:text-gray-400' => $statusColor === 'gray',
-                ]),
                 'indicator_icon_classes' => Arr::toCssClasses([
                     'h-5 w-5 opacity-20',
                     'text-primary-500' => $isLeader,
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php b/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
index 11403e0..d1c5c3a 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/SubmissionDetailPage.php
@@ -4,7 +4,9 @@
 
 use App\Enums\AssignmentType;
 use App\Filament\Actions\BackAction;
+use App\Filament\Resources\Learning\Assignments\Actions\MarkAsSentAction;
 use App\Filament\Resources\Learning\Assignments\AssignmentResource;
+use App\Filament\Support\SystemNotification;
 use App\Models\Assignment;
 use App\Models\AssignmentSubmission;
 use Filament\Actions\Action;
@@ -53,6 +55,14 @@ public function statCards(): array
                 'icon' => 'heroicon-o-chart-bar',
                 'color_classes' => 'bg-primary-100 dark:bg-primary-900/30 text-primary-700 dark:text-primary-400',
             ],
+            [
+                'label' => 'Status Dosen',
+                'value' => $this->record?->is_sent_to_lecturer ? 'SUDAH TERKIRIM' : 'BELUM TERKIRIM',
+                'icon' => $this->record?->is_sent_to_lecturer ? 'heroicon-o-check-badge' : 'heroicon-o-clock',
+                'color_classes' => $this->record?->is_sent_to_lecturer
+                    ? 'bg-success-500 text-white shadow-lg shadow-success-200 dark:shadow-none'
+                    : 'bg-amber-100 dark:bg-amber-900/30 text-amber-700 dark:text-amber-400',
+            ],
         ];
     }
 
@@ -164,9 +174,18 @@ public function assignmentSummary(): array
             'due_date' => $this->record?->due_date?->translatedFormat('l, d F Y H:i'),
             'type' => $this->record?->type->value,
             'is_overdue' => $this->isOverdue,
+            'is_sent_to_lecturer' => $this->record?->is_sent_to_lecturer,
         ];
     }
 
+    #[Computed]
+    public function sectionIcon(): string
+    {
+        return SystemNotification::getNotifStyle() === \App\Enums\NotifStyle::Cheerful
+            ? 'heroicon-o-document-magnifying-glass'
+            : 'heroicon-o-document-text';
+    }
+
     public function previewSubmissionAction(): Action
     {
         return Action::make('previewSubmission')
@@ -186,6 +205,8 @@ public function previewSubmissionAction(): Action
     protected function getHeaderActions(): array
     {
         return [
+            MarkAsSentAction::make()
+                ->record($this->record),
 
             BackAction::make()
                 ->url(AssignmentResource::getUrl()),
diff --git a/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php b/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
index 2460f17..4bb2285 100644
--- a/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
+++ b/app/Filament/Resources/Learning/Assignments/Pages/SubmitAssignmentPage.php
@@ -56,6 +56,9 @@ public function form(Schema $schema): Schema
     #[Computed]
     public function statusCards(): array
     {
+        $isSent = $this->record->is_sent_to_lecturer;
+        $existing = $this->existingSubmission;
+
         return [
             [
                 'label' => 'Batas Waktu',
@@ -71,14 +74,28 @@ public function statusCards(): array
             ],
             [
                 'label' => 'Status Pengumpulan',
-                'value' => $this->isOverdue ? 'Ditutup' : 'Terbuka',
-                'icon' => $this->isOverdue ? 'heroicon-o-lock-closed' : 'heroicon-o-check-circle',
-                'is_danger' => $this->isOverdue,
-                'is_success' => ! $this->isOverdue,
+                'value' => $existing ? 'Sudah Dikumpulkan' : ($isSent ? 'Terlambat & Terkunci' : ($this->isOverdue ? 'Belum (Masih Terbuka)' : 'Belum Dikumpulkan')),
+                'icon' => $existing ? 'heroicon-o-check-circle' : ($isSent ? 'heroicon-o-lock-closed' : 'heroicon-o-arrow-up-tray'),
+                'is_success' => (bool) $existing,
+                'is_danger' => ! $existing && $isSent,
+                'is_warning' => ! $existing && ! $isSent && $this->isOverdue,
                 'icon_classes' => Arr::toCssClasses([
                     'flex h-9 w-9 shrink-0 items-center justify-center rounded-lg',
-                    'bg-danger-50 dark:bg-danger-900/20 text-danger-600' => $this->isOverdue,
-                    'bg-success-50 dark:bg-success-900/20 text-success-600' => ! $this->isOverdue,
+                    'bg-success-50 dark:bg-success-900/20 text-success-600' => $existing,
+                    'bg-danger-50 dark:bg-danger-900/20 text-danger-600' => ! $existing && $isSent,
+                    'bg-warning-50 dark:bg-warning-900/20 text-warning-600' => ! $existing && ! $isSent && $this->isOverdue,
+                ]),
+            ],
+            [
+                'label' => 'Status ke Dosen',
+                'value' => $isSent ? 'Telah Dikirim' : 'Belum Dikirim',
+                'icon' => $isSent ? 'heroicon-o-paper-airplane' : 'heroicon-o-clock',
+                'is_success' => $isSent,
+                'badge' => $isSent ? '(Kunci Aktif)' : '(Masih Terbuka)',
+                'icon_classes' => Arr::toCssClasses([
+                    'flex h-9 w-9 shrink-0 items-center justify-center rounded-lg',
+                    'bg-success-50 dark:bg-success-900/20 text-success-600' => $isSent,
+                    'bg-gray-100 dark:bg-gray-800 text-gray-500' => ! $isSent,
                 ]),
             ],
         ];
@@ -243,6 +260,13 @@ public function submit(): void
             return;
         }
 
+        if ($assignment->is_sent_to_lecturer) {
+            SystemNotification::send('submission_locked', type: 'danger')
+                ->send();
+
+            return;
+        }
+
         if (! $this->canSubmit) {
             SystemNotification::send('submission_not_leader', type: 'danger')
                 ->send();
@@ -313,7 +337,7 @@ protected function getHeaderActions(): array
 
         return [
             BackAction::make()
-                ->url(url()->previous() ?? AssignmentResource::getUrl('index')),
+                ->url(url()->previous() !== AssignmentResource::getUrl('submit', ['record' => $this->record->id]) ? url()->previous() : AssignmentResource::getUrl('index')),
         ];
     }
 }
diff --git a/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php b/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
index 1b0fa7e..4640ccc 100644
--- a/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
+++ b/app/Filament/Resources/Learning/Attendances/Pages/ManageAttendances.php
@@ -2,6 +2,7 @@
 
 namespace App\Filament\Resources\Learning\Attendances\Pages;
 
+use App\Enums\NotifStyle;
 use App\Filament\Resources\Learning\Attendances\AttendanceResource;
 use App\Filament\Support\SystemNotification;
 use App\Models\Attendance;
@@ -71,6 +72,22 @@ public function emptyDescription(): string
         return SystemNotification::getByKey('labels.empty_attendance.description');
     }
 
+    #[Computed]
+    public function sectionIcon(): string
+    {
+        return SystemNotification::getNotifStyle() === NotifStyle::Cheerful
+            ? 'heroicon-o-hand-raised'
+            : 'heroicon-o-clipboard-document-check';
+    }
+
+    #[Computed]
+    public function historyIcon(): string
+    {
+        return SystemNotification::getNotifStyle() === NotifStyle::Cheerful
+            ? 'heroicon-o-clock'
+            : 'heroicon-o-archive-box';
+    }
+
     public function getSchedules()
     {
         /** @var User|null $user */
diff --git a/app/Models/Assignment.php b/app/Models/Assignment.php
index f70cd79..f4dc63c 100644
--- a/app/Models/Assignment.php
+++ b/app/Models/Assignment.php
@@ -30,6 +30,7 @@ protected function casts(): array
         return [
             'due_date' => 'datetime',
             'type' => AssignmentType::class,
+            'is_sent_to_lecturer' => 'boolean',
         ];
     }
 
diff --git a/database/migrations/2026_04_07_094148_add_is_sent_to_lecturer_to_assignments_table.php b/database/migrations/2026_04_07_094148_add_is_sent_to_lecturer_to_assignments_table.php
new file mode 100644
index 0000000..d4606d6
--- /dev/null
+++ b/database/migrations/2026_04_07_094148_add_is_sent_to_lecturer_to_assignments_table.php
@@ -0,0 +1,30 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        if (!Schema::hasColumn('assignments', 'is_sent_to_lecturer')) {
+            Schema::table('assignments', function (Blueprint $table) {
+                $table->boolean('is_sent_to_lecturer')->default(false)->after('due_date');
+            });
+        }
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('assignments', function (Blueprint $table) {
+            $table->dropColumn('is_sent_to_lecturer');
+        });
+    }
+};
diff --git a/lang/id/notif.php b/lang/id/notif.php
index 32dba5a..826b890 100644
--- a/lang/id/notif.php
+++ b/lang/id/notif.php
@@ -145,6 +145,18 @@
             'title' => 'Mantap! Sudah Dibaca ✅✨',
             'body' => 'Pembaruan ":title" sudah ditandai. Makin update makin jago! 🚀🔥',
         ],
+        'assignment_sent' => [
+            'title' => 'Tugas Berhasil Dikirim! 🚀✨',
+            'body' => 'Tugas kolektif sudah berhasil ditandai terkirim ke dosen. Status pengumpulan resmi ditutup! 🔒',
+        ],
+        'assignment_unlocked' => [
+            'title' => 'Kunci Tugas Dibuka! 🔓✨',
+            'body' => 'Mahasiswa sekarang diperbolehkan kembali untuk mengumpulkan atau memperbarui tugas mereka. 📝',
+        ],
+        'submission_locked' => [
+            'title' => 'Tugas Terkunci! 🔒',
+            'body' => 'Mohon maaf, tugas ini sudah ditandai terkirim ke dosen oleh Kosma dan tidak dapat diubah lagi. 🚫',
+        ],
 
         // UI Labels & Descriptions
         'labels' => [
@@ -437,6 +449,18 @@
             'title' => 'Pembaruan Berhasil Ditandai',
             'body' => 'Catatan rilis ":title" telah berhasil ditandai sebagai sudah dibaca.',
         ],
+        'assignment_sent' => [
+            'title' => 'Konfirmasi Pengiriman Berhasil',
+            'body' => 'Seluruh berkas tugas kolektif telah berhasil ditandai sebagai terkirim ke dosen pengampu.',
+        ],
+        'assignment_unlocked' => [
+            'title' => 'Kunci Akses Dibuka',
+            'body' => 'Otoritas pengumpulan tugas telah diaktifkan kembali untuk seluruh mahasiswa terkait.',
+        ],
+        'submission_locked' => [
+            'title' => 'Akses Pengumpulan Ditutup',
+            'body' => 'Tugas ini telah dalam status final (terkirim ke dosen). Perubahan data tidak lagi dimungkinkan.',
+        ],
 
         // UI Labels & Descriptions
         'labels' => [
diff --git a/resources/views/filament/resources/learning/assignments/index.blade.php b/resources/views/filament/resources/learning/assignments/index.blade.php
index cc88264..df51569 100644
--- a/resources/views/filament/resources/learning/assignments/index.blade.php
+++ b/resources/views/filament/resources/learning/assignments/index.blade.php
@@ -19,7 +19,7 @@
                         class="flex flex-1 items-start gap-4 p-5 text-left min-w-0 hover:bg-primary-500/5 transition-colors cursor-pointer">
 
                         <div class="{{ $card->icon_wrapper_classes }} h-12 w-12 mt-1 shrink-0">
-                            <x-filament::icon :icon="$card->status_icon" class="h-6 w-6" />
+                            <x-filament::icon :icon="$card->submission_status->icon" class="h-6 w-6" />
                         </div>
 
                         <div class="flex-1 min-w-0">
@@ -51,11 +51,16 @@ class="inline-flex items-center gap-1.5 rounded-full bg-blue-100 text-blue-700 d
                                     </span>
                                 @endif
 
-                                <span class="{{ $card->status_badge_classes }} px-2.5 py-1 whitespace-nowrap">
-                                    @if ($card->status_icon)
-                                        <x-filament::icon :icon="$card->status_icon" class="h-4 w-4" />
-                                    @endif
-                                    {{ $card->status_label }}
+                                {{-- Status Pengumpulan (Submission Status) --}}
+                                <span class="{{ $card->submission_status->classes }} whitespace-nowrap">
+                                    <x-filament::icon :icon="$card->submission_status->icon" class="h-3.5 w-3.5" />
+                                    {{ $card->submission_status->label }}
+                                </span>
+
+                                {{-- Status Pengiriman ke Dosen (Delivery Status) --}}
+                                <span class="{{ $card->delivery_status->classes }} whitespace-nowrap">
+                                    <x-filament::icon :icon="$card->delivery_status->icon" class="h-3.5 w-3.5" />
+                                    {{ $card->delivery_status->label }}
                                 </span>
 
                                 @if ($card->is_urgent)
@@ -91,6 +96,7 @@ class="flex flex-wrap items-center gap-3 px-5 py-4 border-t border-gray-100 dark
                         @endcan
 
                         @canAny(['Update:Assignment', 'Delete:Assignment'])
+                            {{ ($this->markAsSentAction)(['record' => $card->id]) }}
                             {{ ($this->editAssignmentAction)(['record' => $card->id]) }}
                             {{ ($this->deleteAssignmentAction)(['record' => $card->id]) }}
                         @endcanAny
diff --git a/resources/views/filament/resources/learning/assignments/submission-detail.blade.php b/resources/views/filament/resources/learning/assignments/submission-detail.blade.php
index e012398..6e18b74 100644
--- a/resources/views/filament/resources/learning/assignments/submission-detail.blade.php
+++ b/resources/views/filament/resources/learning/assignments/submission-detail.blade.php
@@ -26,11 +26,18 @@
             style="width: {{ $this->percentage }}%"></div>
     </div>
 
-    <x-filament::section 
-        icon="{{ \App\Filament\Support\SystemNotification::getNotifStyle() === \App\Enums\NotifStyle::Cheerful ? 'heroicon-o-document-magnifying-glass' : 'heroicon-o-document-text' }}" 
+    <x-filament::section
+        icon="{{ $this->sectionIcon }}"
         icon-color="primary"
     >
-        <x-slot name="heading">{{ $this->assignmentSummary['title'] }}</x-slot>
+        <x-slot name="heading">
+            <div class="flex items-center gap-3">
+                {{ $this->assignmentSummary['title'] }}
+                @if ($this->assignmentSummary['is_sent_to_lecturer'])
+                    <x-filament::badge color="success" icon="heroicon-m-check-badge" size="sm">Sudah Dikirim ke Dosen</x-filament::badge>
+                @endif
+            </div>
+        </x-slot>
         <x-slot name="description">
             {{ $this->assignmentSummary['course'] }}
             &nbsp;·&nbsp;
diff --git a/resources/views/filament/resources/learning/assignments/submit-assignment.blade.php b/resources/views/filament/resources/learning/assignments/submit-assignment.blade.php
index 05a17f0..88dafd4 100644
--- a/resources/views/filament/resources/learning/assignments/submit-assignment.blade.php
+++ b/resources/views/filament/resources/learning/assignments/submit-assignment.blade.php
@@ -5,7 +5,7 @@
             <x-slot name="heading">{{ $this->record->title }}</x-slot>
             <x-slot name="description">{{ $this->record->course?->name ?? '-' }}</x-slot>
 
-            <div class="grid grid-cols-1 sm:grid-cols-2 gap-3 mb-4">
+            <div class="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-3 mb-4">
                 @foreach ($this->statusCards as $card)
                     <div class="flex items-center gap-3 rounded-lg border border-gray-200 dark:border-gray-700 p-3">
                         <div class="{{ $card['icon_classes'] }}">
@@ -44,29 +44,28 @@ class="block border-0"></iframe>
             @endif
         </x-filament::section>
 
-        @if ($this->isOverdue)
+        {{-- Kondisi Form: Muncul jika BELUM dikirim ke dosen --}}
+        @if ($this->record->is_sent_to_lecturer)
             <x-filament::section :icon="$this->overdueIcon" icon-color="danger">
-                <x-slot name="heading">{{ $this->overdueHeading }}</x-slot>
-                <x-slot name="description">{{ $this->overdueDescription }}</x-slot>
+                <x-slot name="heading">Penerimaan Tugas Ditutup</x-slot>
+                <x-slot name="description">Tugas ini sudah dikirim ke dosen oleh Kosma dan tidak dapat diubah lagi.</x-slot>
 
                 <div class="flex items-center gap-3 mb-5">
                     <div
                         class="flex h-10 w-10 shrink-0 items-center justify-center rounded-full bg-danger-50 dark:bg-danger-900/20 text-danger-600">
                         <x-filament::icon icon="heroicon-o-lock-closed" class="h-5 w-5" />
                     </div>
-                    <div class="flex flex-wrap items-center gap-2">
-                        <x-filament::badge :color="$this->submissionStatus->badge_color" size="lg">
-                            {{ $this->submissionStatus->badge_label }}
-                        </x-filament::badge>
+                    <div class="flex flex-wrap items-center gap-2 text-sm text-gray-600 dark:text-gray-400">
+                        Tugas sudah dikirim ke dosen pada status final.
                     </div>
                 </div>
 
                 @if ($url = $this->getSubmissionFileUrl())
                     <div>
-                        <p class="text-xs font-medium text-gray-500 dark:text-gray-400 mb-2">File yang Dikumpulkan</p>
+                        <p class="text-xs font-medium text-gray-500 dark:text-gray-400 mb-2">File yang Terakhir Dikumpulkan</p>
                         <div
                             class="rounded-lg overflow-hidden border border-gray-200 dark:border-gray-700 bg-gray-50 dark:bg-gray-900">
-                            <iframe src="{{ $url }}" width="100%" height="500"
+                            <iframe src="{{ $url }}" width="100%" height="400"
                                 class="block border-0"></iframe>
                         </div>
                     </div>
@@ -96,6 +95,16 @@ class="block border-0"></iframe>
                 @endif
             </x-filament::section>
         @else
+            @if ($this->isOverdue)
+                <div class="p-4 rounded-xl border border-warning-200 bg-warning-50 dark:bg-warning-900/10 dark:border-warning-900/20 flex gap-3">
+                    <x-filament::icon icon="heroicon-m-exclamation-triangle" class="h-5 w-5 text-warning-600 shrink-0" />
+                    <div>
+                        <p class="text-sm font-bold text-warning-800 dark:text-warning-400">Tenggat Waktu Sudah Terlewat</p>
+                        <p class="text-xs text-warning-700 dark:text-warning-500 mt-1">Anda masih diperbolehkan mengumpulkan tugas karena belum dikirim ke dosen oleh Kosma.</p>
+                    </div>
+                </div>
+            @endif
+
             <x-filament::section :icon="$this->submissionIcon" icon-color="primary">
                 <x-slot name="heading">{{ $this->submissionHeading }}</x-slot>
                 <x-slot name="description">{{ $this->submissionDescription }}</x-slot>
diff --git a/resources/views/filament/resources/learning/attendances/index.blade.php b/resources/views/filament/resources/learning/attendances/index.blade.php
index 9ef597f..96479be 100644
--- a/resources/views/filament/resources/learning/attendances/index.blade.php
+++ b/resources/views/filament/resources/learning/attendances/index.blade.php
@@ -1,6 +1,6 @@
 <x-filament-panels::page>
-    <x-filament::section 
-        icon="{{ \App\Filament\Support\SystemNotification::getNotifStyle() === \App\Enums\NotifStyle::Cheerful ? 'heroicon-o-hand-raised' : 'heroicon-o-clipboard-document-check' }}" 
+    <x-filament::section
+        icon="{{ $this->sectionIcon }}"
         icon-color="primary"
     >
         <x-slot name="heading">{{ $this->heading }}</x-slot>
@@ -102,7 +102,7 @@ class="text-[10px] font-bold text-gray-400 uppercase tracking-widest leading-non
                 @endforeach
             </div>
         @else
-            <x-filament::empty-state icon="heroicon-o-finger-print" 
+            <x-filament::empty-state icon="heroicon-o-finger-print"
                 heading="{{ $this->emptyHeading }}"
                 description="{{ $this->emptyDescription }}"
                 iconColor="gray">
@@ -111,8 +111,8 @@ class="text-[10px] font-bold text-gray-400 uppercase tracking-widest leading-non
 
     </x-filament::section>
 
-    <x-filament::section 
-        icon="{{ \App\Filament\Support\SystemNotification::getNotifStyle() === \App\Enums\NotifStyle::Cheerful ? 'heroicon-o-clock' : 'heroicon-o-archive-box' }}" 
+    <x-filament::section
+        icon="{{ $this->historyIcon }}"
         icon-color="gray"
     >
         <x-slot name="heading">{{ $this->historyHeading }}</x-slot>
diff --git a/tests/Feature/AssignmentTest.php b/tests/Feature/AssignmentTest.php
index 4260f08..4def8a9 100644
--- a/tests/Feature/AssignmentTest.php
+++ b/tests/Feature/AssignmentTest.php
@@ -366,3 +366,71 @@
             ->assertSee($assignment->title);
     });
 });
+
+describe('Assignment Delivery Status', function () {
+    beforeEach(function () {
+        $this->kosmaUser = User::factory()->create();
+        $this->kosmaUser->assignRole(RoleEnum::Kosma);
+        $this->kosmaUser->givePermissionTo(['ViewAny:Assignment', 'View:Assignment', 'View:CourseSchedule']);
+
+        $this->studentUser = User::factory()->create();
+        $this->studentUser->assignRole(RoleEnum::Student);
+        $this->studentUser->givePermissionTo(['ViewAny:Assignment', 'View:CourseSchedule']);
+        $this->student = Student::factory()->create(['user_id' => $this->studentUser->id]);
+
+        $this->currentSemester = app(GeneralSettings::class)->current_semester;
+    });
+
+    it('can toggle assignment delivery status (Mark as Sent)', function () {
+        $assignment = Assignment::factory()->create([
+            'is_sent_to_lecturer' => false,
+        ]);
+
+        $this->actingAs($this->kosmaUser);
+
+        Livewire::test(ListAssignments::class)
+            ->callAction('markAsSentAction', [], ['record' => $assignment->id]);
+
+        expect($assignment->refresh()->is_sent_to_lecturer)->toBeTrue();
+
+        Livewire::test(ListAssignments::class)
+            ->callAction('markAsSentAction', [], ['record' => $assignment->id]);
+
+        expect($assignment->refresh()->is_sent_to_lecturer)->toBeFalse();
+    });
+
+    it('allows students to submit overdue assignments if not yet sent to lecturer', function () {
+        $assignment = Assignment::factory()->create([
+            'due_date' => now()->subDays(2)->toDateTimeString(), // Far enough in the past
+            'is_sent_to_lecturer' => false,
+            'type' => AssignmentType::Individual,
+        ]);
+        $assignment->students()->attach($this->student->id);
+        $assignment->course->update(['semester' => $this->currentSemester]);
+
+        $this->actingAs($this->studentUser);
+
+        Livewire::test(SubmitAssignmentPage::class, ['record' => $assignment])
+            ->assertSuccessful()
+            ->assertSet('isOverdue', true)
+            ->assertSet('canSubmit', true)
+            ->assertSee('Tenggat Waktu Sudah Terlewat');
+    });
+
+    it('prevents students from submitting if assignment is marked as sent to lecturer', function () {
+        $assignment = Assignment::factory()->create([
+            'due_date' => now()->addDay(),
+            'is_sent_to_lecturer' => true,
+        ]);
+        $assignment->students()->attach($this->student->id);
+        $assignment->course->update(['semester' => $this->currentSemester]);
+
+        $this->actingAs($this->studentUser);
+
+        Livewire::test(SubmitAssignmentPage::class, ['record' => $assignment])
+            ->assertSuccessful()
+            ->assertSee('Penerimaan Tugas Ditutup')
+            ->assertDontSeeHtml('type="file"');
+    });
+});
+