diff --git a/techblog_cms/static/js/main.js b/techblog_cms/static/js/main.js
index fd47f2c..5175c52 100644
--- a/techblog_cms/static/js/main.js
+++ b/techblog_cms/static/js/main.js
@@ -1,4 +1,41 @@
 document.addEventListener('DOMContentLoaded', function() {
-    // Initialize any JavaScript functionality
-    // Mobile menu toggle functionality can be added here
+    const menuButton = document.getElementById('mobile-menu-button');
+    const mobileMenu = document.getElementById('mobile-menu');
+
+    if (!menuButton || !mobileMenu) {
+        return;
+    }
+
+    const closeMenu = () => {
+        mobileMenu.classList.add('hidden');
+        menuButton.setAttribute('aria-expanded', 'false');
+    };
+
+    menuButton.addEventListener('click', (event) => {
+        event.preventDefault();
+        const isHidden = mobileMenu.classList.contains('hidden');
+
+        if (isHidden) {
+            mobileMenu.classList.remove('hidden');
+            menuButton.setAttribute('aria-expanded', 'true');
+        } else {
+            closeMenu();
+        }
+    });
+
+    mobileMenu.querySelectorAll('a').forEach((link) => {
+        link.addEventListener('click', () => {
+            closeMenu();
+        });
+    });
+
+    document.addEventListener('click', (event) => {
+        if (
+            !mobileMenu.classList.contains('hidden') &&
+            !mobileMenu.contains(event.target) &&
+            !menuButton.contains(event.target)
+        ) {
+            closeMenu();
+        }
+    });
 });
\ No newline at end of file
diff --git a/techblog_cms/templates/base.html b/techblog_cms/templates/base.html
index 5c4964c..608fddf 100644
--- a/techblog_cms/templates/base.html
+++ b/techblog_cms/templates/base.html
@@ -31,12 +31,12 @@
         {% include 'components/header.html' %}
     {% endblock %}
 
-    <div class="container mx-auto mt-6 px-4">
-        <div class="flex flex-col md:flex-row">
+    <div class="container mx-auto px-4 pt-24 md:pt-28">
+        <div class="flex flex-col md:flex-row md:items-start gap-8">
             {% block sidebar %}
                 {% include 'components/sidebar.html' %}
             {% endblock %}
-            
+
             {% block content %}
                 {% include 'components/main_content.html' %}
             {% endblock %}
@@ -44,7 +44,7 @@
     </div>
 
     {% block scripts %}
-    <script src="{% static 'js/article.js' %}"></script>
+    <script src="{% static 'js/main.js' %}"></script>
     {% endblock %}
 </body>
 </html>
diff --git a/techblog_cms/templates/components/header.html b/techblog_cms/templates/components/header.html
index d0f2368..64d43fc 100644
--- a/techblog_cms/templates/components/header.html
+++ b/techblog_cms/templates/components/header.html
@@ -1,40 +1,54 @@
 <header class="fixed top-0 w-full bg-white shadow-sm z-50">
     <nav class="container mx-auto px-4">
-        <div class="flex flex-wrap items-center justify-between h-20">
+        <div class="flex items-center justify-between h-20">
             <!-- Logo -->
-            <a href="{% url 'home' %}" class="text-xl font-bold text-gray-800">
+            <a href="{% url 'home' %}" class="flex-shrink-0 text-xl font-bold text-gray-800">
                 {{ blog_title|default:"TechBlog CMS" }}
             </a>
-            
+
             <!-- Search Box (medium screens and up) -->
             <div class="hidden md:block flex-grow max-w-xl mx-4">
-                <input type="text" id="searchBox" placeholder="キーワードとユーザー検索" 
+                <input type="text" id="searchBox" placeholder="キーワードとユーザー検索"
                     class="w-full px-4 py-2 border border-gray-300 rounded-full focus:outline-none focus:ring-2 focus:ring-blue-500">
             </div>
 
-            <!-- Mobile menu button -->
-            <button id="mobile-menu-button" class="md:hidden">
-                <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 6h16M4 12h16M4 18h16"></path>
-                </svg>
-            </button>
+            <div class="flex items-center space-x-3">
+                <!-- Navigation and Auth buttons (desktop) -->
+                <div class="hidden md:flex items-center space-x-4">
+                    <a href="{% url 'home' %}" class="text-gray-600 hover:text-gray-900">Home</a>
+                    <a href="{% url 'article_list' %}" class="text-gray-600 hover:text-gray-900">Articles</a>
+                    <a href="{% url 'categories' %}" class="text-gray-600 hover:text-gray-900">Categories</a>
+                    <a href="{% url 'login' %}" class="px-4 py-2 bg-blue-500 text-white font-semibold rounded hover:bg-blue-600 transition">
+                        ログイン
+                    </a>
+                    <a href="#" class="text-blue-500 hover:underline">ユーザー登録</a>
+                </div>
 
-            <!-- Navigation and Auth buttons -->
-            <div class="hidden md:flex items-center space-x-4">
-                <a href="{% url 'home' %}" class="text-gray-600 hover:text-gray-900">Home</a>
-                <a href="{% url 'article_list' %}" class="text-gray-600 hover:text-gray-900">Articles</a>
-                <a href="{% url 'categories' %}" class="text-gray-600 hover:text-gray-900">Categories</a>
-                <a href="{% url 'login' %}" class="px-4 py-2 bg-blue-500 text-white font-semibold rounded hover:bg-blue-600 transition">
-                    ログイン
-                </a>
-                <a href="#" class="text-blue-500 hover:underline">ユーザー登録</a>
+                <!-- Mobile menu button -->
+                <button id="mobile-menu-button" type="button"
+                        class="md:hidden inline-flex items-center justify-center p-2 rounded-md text-gray-700 hover:text-gray-900 hover:bg-gray-100 focus:outline-none focus:ring-2 focus:ring-inset focus:ring-blue-500"
+                        aria-controls="mobile-menu" aria-expanded="false" aria-label="メインメニューを開く">
+                    <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 6h16M4 12h16M4 18h16"></path>
+                    </svg>
+                </button>
             </div>
         </div>
 
         <!-- Mobile search (visible on mobile only) -->
         <div class="md:hidden pb-4">
-            <input type="text" id="mobileSearchBox" placeholder="キーワードとユーザー検索" 
+            <input type="text" id="mobileSearchBox" placeholder="キーワードとユーザー検索"
                 class="w-full px-4 py-2 border border-gray-300 rounded-full focus:outline-none focus:ring-2 focus:ring-blue-500">
         </div>
+
+        <!-- Mobile navigation menu -->
+        <div id="mobile-menu" class="hidden md:hidden pb-4 border-t border-gray-200">
+            <div class="pt-4 flex flex-col space-y-3">
+                <a href="{% url 'login' %}" class="text-gray-700 hover:text-blue-600 font-medium">ログイン</a>
+                <a href="{% url 'article_list' %}" class="text-gray-700 hover:text-blue-600 font-medium">記事一覧</a>
+                <a href="{% url 'categories' %}" class="text-gray-700 hover:text-blue-600 font-medium">カテゴリ一覧</a>
+                <a href="{% url 'tags' %}" class="text-gray-700 hover:text-blue-600 font-medium">タグ一覧</a>
+            </div>
+        </div>
     </nav>
 </header>
diff --git a/techblog_cms/templates/components/sidebar.html b/techblog_cms/templates/components/sidebar.html
index 06f458f..22c2e95 100644
--- a/techblog_cms/templates/components/sidebar.html
+++ b/techblog_cms/templates/components/sidebar.html
@@ -1,4 +1,4 @@
-<aside class="sidebar w-full md:w-64 md:mr-8">
+<aside class="sidebar hidden md:block md:w-64 md:flex-shrink-0">
     <div class="mb-8">
         <h3 class="text-lg font-semibold mb-4">Categories</h3>
         <ul class="space-y-2">
diff --git a/techblog_cms/templates/tag_detail.html b/techblog_cms/templates/tag_detail.html
new file mode 100644
index 0000000..d4a849f
--- /dev/null
+++ b/techblog_cms/templates/tag_detail.html
@@ -0,0 +1,34 @@
+{% extends 'base.html' %}
+
+{% block title %}{{ tag.name }} - Tags - {{ block.super }}{% endblock %}
+
+{% block content %}
+<div class="bg-white rounded-lg shadow-md p-6">
+    <div class="flex flex-wrap items-center justify-between gap-4">
+        <div>
+            <h1 class="text-3xl font-bold text-gray-800">#{{ tag.name }}</h1>
+            <p class="text-gray-600 mt-2">{{ articles|length }} 件の記事がこのタグに紐付いています。</p>
+        </div>
+        <a href="{% url 'tags' %}" class="text-blue-500 hover:underline">← タグ一覧に戻る</a>
+    </div>
+
+    <div class="mt-6 space-y-4">
+        {% for article in articles %}
+        <div class="border-b border-gray-200 pb-4">
+            <h2 class="text-xl font-semibold text-blue-600 hover:text-blue-800">
+                <a href="{% url 'article_detail' article.slug %}">{{ article.title }}</a>
+            </h2>
+            <p class="text-gray-600 mt-2">{{ article.excerpt|default:article.content|truncatewords:30 }}</p>
+            <div class="text-sm text-gray-500 mt-2">
+                <span>Published: {{ article.created_at|date:"M d, Y" }}</span>
+                {% if article.category %}
+                <span class="ml-4">Category: {{ article.category.name }}</span>
+                {% endif %}
+            </div>
+        </div>
+        {% empty %}
+        <p class="text-gray-500">このタグが付いた記事はまだありません。</p>
+        {% endfor %}
+    </div>
+</div>
+{% endblock %}
diff --git a/techblog_cms/templates/tag_list.html b/techblog_cms/templates/tag_list.html
new file mode 100644
index 0000000..1d16cac
--- /dev/null
+++ b/techblog_cms/templates/tag_list.html
@@ -0,0 +1,22 @@
+{% extends 'base.html' %}
+
+{% block title %}Tags - {{ block.super }}{% endblock %}
+
+{% block content %}
+<div class="bg-white rounded-lg shadow-md p-6">
+    <h1 class="text-3xl font-bold text-gray-800 mb-6">タグ一覧</h1>
+
+    {% if tags %}
+    <div class="flex flex-wrap gap-3">
+        {% for tag in tags %}
+        <a href="{% url 'tag' slug=tag.slug %}"
+           class="px-4 py-2 bg-gray-100 text-gray-700 rounded-full hover:bg-blue-100 hover:text-blue-700 transition">
+            #{{ tag.name }}
+        </a>
+        {% endfor %}
+    </div>
+    {% else %}
+    <p class="text-gray-500">タグはまだ登録されていません。</p>
+    {% endif %}
+</div>
+{% endblock %}
diff --git a/techblog_cms/urls.py b/techblog_cms/urls.py
index cd7ac80..a849e03 100644
--- a/techblog_cms/urls.py
+++ b/techblog_cms/urls.py
@@ -12,6 +12,8 @@
     re_path(r'^articles/(?P<slug>[\w\-]+)/$', views.article_detail_view, name='article_detail'),
     path('categories/', views.categories_view, name='categories'),
     path('categories/<slug:slug>/', views.category_view, name='category'),
+    path('tags/', views.tags_view, name='tags'),
+    path('tags/<slug:slug>/', views.tag_view, name='tag'),
     path('login/', views.login_view, name='login'),
     path('logout/', views.logout_view, name='logout'),
     path('dashboard/', views.dashboard_view, name='dashboard'),
diff --git a/techblog_cms/views.py b/techblog_cms/views.py
index 1934775..980e20b 100644
--- a/techblog_cms/views.py
+++ b/techblog_cms/views.py
@@ -5,7 +5,7 @@
 from django.views.decorators.http import require_http_methods
 from django.views.decorators.csrf import csrf_exempt
 from django.core.paginator import Paginator
-from .models import Article, Category
+from .models import Article, Category, Tag
 from techblog_cms.templatetags.markdown_filter import markdown_to_html
 from django.conf import settings
 from django.http import HttpResponseNotFound
@@ -18,20 +18,91 @@ def index(request):
 
 def home_view(request):
     articles = Article.objects.filter(published=True).order_by('-created_at')[:10]
-    return render(request, 'home.html', {'articles': articles})
+    categories = Category.objects.all()
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'home.html',
+        {
+            'articles': articles,
+            'categories': categories,
+            'tags': tags,
+        },
+    )
 
 def article_list_view(request):
     articles = Article.objects.filter(published=True).order_by('-created_at')
-    return render(request, 'article_list.html', {'articles': articles})
+    categories = Category.objects.all()
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'article_list.html',
+        {
+            'articles': articles,
+            'categories': categories,
+            'tags': tags,
+        },
+    )
 
 def categories_view(request):
     categories = Category.objects.all()
-    return render(request, 'category_list.html', {'categories': categories})
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'category_list.html',
+        {
+            'categories': categories,
+            'tags': tags,
+        },
+    )
 
 def category_view(request, slug):
     category = get_object_or_404(Category, slug=slug)
     articles = category.article_set.filter(published=True).order_by('-created_at')
-    return render(request, 'category_detail.html', {'category': category, 'articles': articles})
+    categories = Category.objects.all()
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'category_detail.html',
+        {
+            'category': category,
+            'articles': articles,
+            'categories': categories,
+            'tags': tags,
+        },
+    )
+
+def tags_view(request):
+    tags = Tag.objects.all()
+    categories = Category.objects.all()
+    return render(
+        request,
+        'tag_list.html',
+        {
+            'tags': tags,
+            'categories': categories,
+        },
+    )
+
+def tag_view(request, slug):
+    tag = get_object_or_404(Tag, slug=slug)
+    if request.user.is_authenticated:
+        articles = tag.article_set.order_by('-created_at')
+    else:
+        articles = tag.article_set.filter(published=True).order_by('-created_at')
+
+    categories = Category.objects.all()
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'tag_detail.html',
+        {
+            'tag': tag,
+            'articles': articles,
+            'categories': categories,
+            'tags': tags,
+        },
+    )
 
 def article_detail_view(request, slug):
     # ログインしている場合は下書き記事も表示可能
@@ -39,7 +110,17 @@ def article_detail_view(request, slug):
         article = get_object_or_404(Article, slug=slug)
     else:
         article = get_object_or_404(Article, slug=slug, published=True)
-    return render(request, 'article_detail.html', {'article': article})
+    categories = Category.objects.all()
+    tags = Tag.objects.all()
+    return render(
+        request,
+        'article_detail.html',
+        {
+            'article': article,
+            'categories': categories,
+            'tags': tags,
+        },
+    )
 def admin_guard(request):
     """Direct /admin/ access guard. Show 404 if HIDE_ADMIN_URL is True."""
     if getattr(settings, 'HIDE_ADMIN_URL', False):