diff --git a/courses/views.py b/courses/views.py
index 8a33bbb..ca9fb22 100644
--- a/courses/views.py
+++ b/courses/views.py
@@ -3,6 +3,7 @@ from django.urls import reverse
 from django.views import generic
 from django.db.models import Prefetch
 from .models import Course, Lesson, Module, Comment
+from progression.models import Progression
 from .forms import CommentForm
 
 def list_courses(request):
@@ -23,9 +24,23 @@ def show(request, course_name, course_id):
         .order_by('order')
     )
 
+    # Récupération de la progression de l'utilisateur sur le cours
+    user_progress = None
+    completed_lesson_ids = []  # On prépare une liste vide par défaut
+
+    if request.user.is_authenticated:
+        user_progress = Progression.objects.filter(user=request.user, course=course).first()
+
+        # 2. S'il y a une progression, on extrait juste les IDs des leçons finies
+        if user_progress:
+            # values_list renvoie une liste simple : [1, 5, 12] au lieu d'objets lourds
+            completed_lesson_ids = user_progress.completed_lessons.values_list('id', flat=True)
+
     context = {
         'course': course,
         'lessons': lessons,
+        'user_progress': user_progress,
+        'completed_lesson_ids': completed_lesson_ids,
     }
     return render(request, 'courses/show.html', context)
 
@@ -105,6 +120,18 @@ def lesson_detail(request, course_slug, module_slug, lesson_slug):
         .order_by('created_at')
     )
 
+    # Récupération de la progression de l'utilisateur sur le cours
+    user_progress = None
+    completed_lesson_ids = []  # On prépare une liste vide par défaut
+
+    if request.user.is_authenticated:
+        user_progress = Progression.objects.filter(user=request.user, course=course).first()
+
+        # 2. S'il y a une progression, on extrait juste les IDs des leçons finies
+        if user_progress:
+            # values_list renvoie une liste simple : [1, 5, 12] au lieu d'objets lourds
+            completed_lesson_ids = user_progress.completed_lessons.values_list('id', flat=True)
+
     context = {
         'course': course,
         'module': module,
@@ -114,5 +141,7 @@ def lesson_detail(request, course_slug, module_slug, lesson_slug):
         'comment_form': form,
         'prev_lesson': prev_lesson,
         'next_lesson': next_lesson,
+        'user_progress': user_progress,
+        'completed_lesson_ids': completed_lesson_ids,
     }
     return render(request, 'courses/lesson.html', context)
\ No newline at end of file
diff --git a/devart/urls.py b/devart/urls.py
index b46feda..17cb4e7 100644
--- a/devart/urls.py
+++ b/devart/urls.py
@@ -43,7 +43,7 @@ urlpatterns = [
     path('', include('home.urls')),
     path('courses/', include('courses.urls')),
     path('users/', include('users.urls')),
-
+    path('progression/', include('progression.urls')),
     path('blog/', include('blog.urls')),
 
     path('sitemap.xml', sitemap, {'sitemaps': sitemaps_dict}, name='django.contrib.sitemaps.views.sitemap'),
diff --git a/progression/urls.py b/progression/urls.py
index a2fd910..cef076c 100644
--- a/progression/urls.py
+++ b/progression/urls.py
@@ -2,6 +2,9 @@ from django.urls import path
 from . import views
 
 app_name = 'progression'
-urlpatterns = [
 
+urlpatterns = [
+    # On ne garde QUE la route AJAX ici.
+    # Les routes 'list', 'detail', etc. doivent rester dans courses/urls.py
+    path('ajax/toggle-lesson/', views.toggle_lesson_completion, name='toggle_lesson'),
 ]
\ No newline at end of file
diff --git a/progression/views.py b/progression/views.py
index 91ea44a..1cee11c 100644
--- a/progression/views.py
+++ b/progression/views.py
@@ -1,3 +1,41 @@
-from django.shortcuts import render
+from django.shortcuts import render, get_object_or_404
+import json
+from django.http import JsonResponse
+from django.views.decorators.http import require_POST
+from django.contrib.auth.decorators import login_required
+from progression.models import Progression
+from courses.models import Lesson
 
-# Create your views here.
+@login_required
+@require_POST
+def toggle_lesson_completion(request):
+    data = json.loads(request.body)
+    lesson_id = data.get('lesson_id')
+
+    lesson = get_object_or_404(Lesson, id=lesson_id)
+    # On remonte au cours via le module (Lesson -> Module -> Course)
+    course = lesson.module.course
+
+    # On récupère ou crée la progression
+    progression, created = Progression.objects.get_or_create(
+        user=request.user,
+        course=course
+    )
+
+    # La logique du Toggle
+    if lesson in progression.completed_lessons.all():
+        progression.completed_lessons.remove(lesson)
+        is_completed = False
+    else:
+        progression.completed_lessons.add(lesson)
+        is_completed = True
+
+        # Mise à jour de la dernière leçon vue
+        progression.last_viewed_lesson = lesson
+        progression.save()
+
+    return JsonResponse({
+        'status': 'success',
+        'is_completed': is_completed,
+        'new_percent': progression.percent_completed
+    })
\ No newline at end of file
diff --git a/static/css/app.css b/static/css/app.css
index d95a712..367520c 100644
--- a/static/css/app.css
+++ b/static/css/app.css
@@ -247,9 +247,9 @@ html { box-sizing: border-box; }
   gap: 6px;
   padding: 2px 8px;
   margin-left: 8px;
-  border-radius: 999px;
+  border-radius: 2px;
   background: var(--accent);
-  color: var(--warning-contrast);
+  color: var(--text);
   font-size: 11px;
   font-weight: 800;
   letter-spacing: .3px;
@@ -259,6 +259,40 @@ html { box-sizing: border-box; }
   white-space: nowrap;
 }
 
+.current-tag {
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
+    padding: 2px 8px;
+    border-radius: 2px;
+    background: var(--primary);
+    color: var(--primary-contrast);
+    font-size: 11px;
+    font-weight: 800;
+    letter-spacing: .3px;
+    line-height: 1.2;
+    vertical-align: middle;
+    text-transform: uppercase;
+    white-space: nowrap;
+}
+
+.completed-tag {
+    display: inline-flex;
+    align-items: center;
+    gap: 6px;
+    padding: 2px 8px;
+    border-radius: 2px;
+    background: var(--success);
+    color: var(--success-contrast);
+    font-size: 11px;
+    font-weight: 800;
+    letter-spacing: .3px;
+    line-height: 1.2;
+    vertical-align: middle;
+    text-transform: uppercase;
+    white-space: nowrap;
+}
+
 .courseToc .tocLink.disabled {
   color: var(--text-muted);
   background: transparent;
@@ -269,6 +303,70 @@ html { box-sizing: border-box; }
   font-weight: 500;
 }
 
+/* Progression des cours */
+
+.progress-container {
+    display: flex;
+    flex-direction: row;
+}
+
+.progress-bar {
+    display: flex;
+    border-radius: var(--r-2);
+    border: 1px solid var(--border);
+    height: 20px;
+    background: var(--neutral-900);
+}
+
+.progress-text {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 4px;
+    color: var(--text);
+    font-size: 12px;
+    margin-left: 10px;
+}
+
+.progress-bar-fill {
+    background: var(--success);
+    height: 100%;
+    border-radius: var(--r-2) 0 0 var(--r-2);
+}
+
+.course-completed {
+    display: flex;
+    flex-direction: row;
+    border-radius: var(--r-2);
+    border: 1px solid var(--border);
+    margin: var(--space-2) 0;
+    background: var(--success);
+}
+
+.course-completed .container {
+    display: flex;
+    flex-direction: column;
+    padding: var(--space-2);
+    height: 100%;
+    vertical-align: middle;
+}
+
+.course-completed .container .icon {
+    color: var(--success-contrast);
+    font-size: 50px;
+}
+
+.course-completed .container .title {
+    color: var(--success-contrast);
+    font-size: 28px;
+    font-weight: 600;
+}
+
+.course-completed .container .content {
+    color: var(--success-contrast);
+    font-size: 14px;
+}
+
 [data-theme='light'] {
   /* Palette: plus nuancé, moins "blanc" */
   --bg: #eef3f7; /* fond légèrement teinté bleu-gris */
diff --git a/templates/courses/partials/_course_header.html b/templates/courses/partials/_course_header.html
index bff069f..33fbd36 100644
--- a/templates/courses/partials/_course_header.html
+++ b/templates/courses/partials/_course_header.html
@@ -4,3 +4,22 @@
     Un cours proposé par&nbsp;<a href="{% url 'another_profile' course.author.id %}">{{ course.author }}</a>
     </p>
 <p>{{ course.content }}</p>
+<strong>Progression pour ce cours</strong>
+{% if user_progress.percent_completed == 100 %}
+    <div class="course-completed">
+        <div class="container">
+            <div class="icon"><i class="fa-solid fa-check"></i></div>
+        </div>
+        <div class="container">
+            <div class="title">Félicitation</div>
+            <div class="content">Tu as terminé(e) ce cours ! Tu peux réellement être fier(e) de toi !!</div>
+        </div>
+    </div>
+{% else %}
+    <div class="progress-container">
+        <div class="progress-bar" style="width: 100%;">
+            <div id="progress-bar-fill" class="progress-bar-fill" style="width: {{ user_progress.percent_completed }}%; height: 100%; transition: width 0.3s;"></div>
+        </div>
+        <div id="progress-text" class="progress-text">{{ user_progress.percent_completed }}%</div>
+    </div>
+{% endif %}
diff --git a/templates/courses/partials/_course_toc.html b/templates/courses/partials/_course_toc.html
index 9039157..1389e55 100644
--- a/templates/courses/partials/_course_toc.html
+++ b/templates/courses/partials/_course_toc.html
@@ -13,7 +13,8 @@
                         <li class="tocLesson{% if lesson and lesson.id == item.id %} current{% endif %}">
                             <a class="tocLink {% if item.is_premium and user.profile.is_premium == False %}premium{% endif %}" href="{% url 'courses:lesson_detail' course.slug item.module.slug item.slug %}">
                                 {{ item.name }} {% if item.is_premium %}<span class="premium-tag">PREMIUM</span>{% endif %}
-                                {% if lesson and lesson.id == item.id %}<span class="tocCurrentTag">(cours actuel)</span>{% endif %}
+                                {% if lesson and lesson.id == item.id %}<span class="current-tag">(cours actuel)</span>{% endif %}
+                                {% if item.id in completed_lesson_ids %}<span class="completed-tag">Terminé</span>{% endif %}
                             </a>
                             {% if lesson and lesson.id == item.id %}
                                 <div class="lessonInline">
@@ -69,6 +70,12 @@
                                         <div class="content-lesson">
                                             <div class="lessonTitle">Ce que l'on voit durant ce cours : </div>
                                             {{ lesson.content|comment_markdown }}
+
+                                            {% if lesson.id in completed_lesson_ids %}
+                                                <button id="btn-complete" data-lesson-id="{{ lesson.id }}" class="btn btn-success">✅ Terminée</button>
+                                            {% else %}
+                                                <button id="btn-complete" data-lesson-id="{{ lesson.id }}" class="btn btn-secondary">Marquer comme terminé</button>
+                                            {% endif %}
                                         </div>
                                     <h3 id="comments">Commentaires</h3>
                                     <div class="lessonComments">
@@ -251,6 +258,64 @@
                                             });
                                         })();
                                     </script>
+
+                                    <!-- Progression Bar -->
+                                    <script>
+                                        document.addEventListener('DOMContentLoaded', function() {
+                                            const btn = document.getElementById('btn-complete');
+                                            const progressBar = document.getElementById('progress-bar-fill');
+                                            const progressText = document.getElementById('progress-text');
+
+                                            btn.addEventListener('click', function() {
+                                                const lessonId = this.getAttribute('data-lesson-id');
+
+                                                // 1. On prépare la requête
+                                                fetch("{% url 'progression:toggle_lesson' %}", {  // Assure-toi que c'est le bon nom dans urls.py
+                                                    method: 'POST',
+                                                    headers: {
+                                                        'Content-Type': 'application/json',
+                                                        'X-CSRFToken': getCookie('csrftoken') // Fonction indispensable pour Django
+                                                    },
+                                                    body: JSON.stringify({
+                                                        'lesson_id': lessonId
+                                                    })
+                                                })
+                                                .then(response => response.json())
+                                                .then(data => {
+                                                    if (data.status === 'success') {
+                                                        // 2. On met à jour le visuel de la barre
+                                                        progressBar.style.width = data.new_percent + '%';
+                                                        progressText.innerText = data.new_percent + '%';
+
+                                                        // 3. On change l'aspect du bouton
+                                                        if (data.is_completed) {
+                                                            btn.innerText = "✅ Terminée";
+                                                            btn.style.backgroundColor = "green";
+                                                        } else {
+                                                            btn.innerText = "Marquer comme terminé";
+                                                            btn.style.backgroundColor = "gray";
+                                                        }
+                                                    }
+                                                });
+                                            });
+
+                                            // --- Fonction Helper pour récupérer le cookie CSRF de Django ---
+                                            function getCookie(name) {
+                                                let cookieValue = null;
+                                                if (document.cookie && document.cookie !== '') {
+                                                    const cookies = document.cookie.split(';');
+                                                    for (let i = 0; i < cookies.length; i++) {
+                                                        const cookie = cookies[i].trim();
+                                                        if (cookie.substring(0, name.length + 1) === (name + '=')) {
+                                                            cookieValue = decodeURIComponent(cookie.substring(name.length + 1));
+                                                            break;
+                                                        }
+                                                    }
+                                                }
+                                                return cookieValue;
+                                            }
+                                        });
+                                        </script>
                                     </div> <!-- /.lessonComments -->
                                 </div> <!-- /.lesson -->
                                 </div> <!-- /.lessonInline -->
diff --git a/templates/layout.html b/templates/layout.html
index 2c3189d..2e7a521 100644
--- a/templates/layout.html
+++ b/templates/layout.html
@@ -39,8 +39,8 @@
         (function() {
             try {
                 var stored = localStorage.getItem('pdz-theme');
-                var prefersLight = window.matchMedia && window.matchMedia('(prefers-color-scheme: light)').matches;
-                var theme = stored || (prefersLight ? 'light' : 'dark');
+                var prefersLight = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;
+                var theme = stored || (prefersLight ? 'dark' : 'light');
                 document.documentElement.setAttribute('data-theme', theme);
                 if (theme === 'light') {
                     var link = document.getElementById('theme-css');