diff --git a/forum/templates/base.html b/forum/templates/base.html
index 7c0bd05..ba19788 100644
--- a/forum/templates/base.html
+++ b/forum/templates/base.html
@@ -44,74 +44,76 @@
 </head>
 {% load static %}
 <body class="d-flex flex-column min-vh-100">
-    <nav class="navbar navbar-expand-lg">
-        <div class="container-fluid">
-            <a class="navbar-brand" href="{% url 'index' %}">
-                <span>
-                    {% include 'forum/icons/chat-left.svg' %}
-                </span>
-                <span>Lean Forum</span>
-            </a>
-            <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="切换导航">
-                <span class="navbar-toggler-icon"></span>
-            </button>
-            <div class="collapse navbar-collapse" id="navbarNav">
-                <ul class="navbar-nav">
-                    <li class="nav-item">
-                        <a class="nav-link active" href="{% url 'index' %}">首页</a>
-                    </li>
-                    {% if not user.is_authenticated %}
-                    <li class="nav-item">
-                        <a class="nav-link" href="{% url 'login' %}">登录</a>
-                    </li>
-                    <li class="nav-item">
-                        <a class="nav-link" href="{% url 'register' %}">注册</a>
-                    </li>
-                    {% endif %}
-                    <li class="nav-item">
-                        <a class="nav-link" href="{% url 'post_list' %}">所有文章</a>
-                    </li>
-                    <li class="nav-item">
-                        <a class="nav-link" href="{% url 'collection_list' %}">合集</a>
-                    </li>
-                    <li class="nav-item">
-                        <a class="nav-link" href="{% url 'about' %}">关于</a>
-                    </li>
-                </ul>
-            </div>
-
-            <div class="d-flex align-items-center ms-auto">
-                <a class="nav-link px-2" href="#" id="theme-toggle" title="切换主题">
-                    <span id="theme-icon"></span>
+    <header>
+        <nav class="navbar navbar-expand-lg">
+            <div class="container-fluid">
+                <a class="navbar-brand" href="{% url 'index' %}">
+                    <span>
+                        {% include 'forum/icons/chat-left.svg' %}
+                    </span>
+                    <span>Lean Forum</span>
                 </a>
-                {% if user.is_authenticated %}
-                <div class="nav-item dropdown">
-                    <a class="nav-link dropdown-toggle" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
-                        <span>
-                            {% include 'forum/icons/person-circle.svg' %}
-                        </span>
-                        <span>{{ user.username }}</span>
-                    </a>
-                    <ul class="dropdown-menu dropdown-menu-end">
-                        <li>
-                            <a class="dropdown-item" href="{% url 'settings' %}">账户设置</a>
+                <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="切换导航">
+                    <span class="navbar-toggler-icon"></span>
+                </button>
+                <div class="collapse navbar-collapse" id="navbarNav">
+                    <ul class="navbar-nav">
+                        <li class="nav-item">
+                            <a class="nav-link active" href="{% url 'index' %}">首页</a>
+                        </li>
+                        {% if not user.is_authenticated %}
+                        <li class="nav-item">
+                            <a class="nav-link" href="{% url 'login' %}">登录</a>
+                        </li>
+                        <li class="nav-item">
+                            <a class="nav-link" href="{% url 'register' %}">注册</a>
+                        </li>
+                        {% endif %}
+                        <li class="nav-item">
+                            <a class="nav-link" href="{% url 'post_list' %}">所有文章</a>
                         </li>
-                        <li>
-                            <form action="{% url 'logout' %}" method="post" class="w-100">
-                                {% csrf_token %}
-                                <button type="submit" class="dropdown-item">登出</button>
-                            </form>
+                        <li class="nav-item">
+                            <a class="nav-link" href="{% url 'collection_list' %}">合集</a>
+                        </li>
+                        <li class="nav-item">
+                            <a class="nav-link" href="{% url 'about' %}">关于</a>
                         </li>
                     </ul>
                 </div>
-                {% endif %}
+
+                <div class="d-flex align-items-center ms-auto">
+                    <a class="nav-link px-2" href="#" id="theme-toggle" title="切换主题">
+                        <span id="theme-icon"></span>
+                    </a>
+                    {% if user.is_authenticated %}
+                    <div class="nav-item dropdown">
+                        <a class="nav-link dropdown-toggle" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
+                            <span>
+                                {% include 'forum/icons/person-circle.svg' %}
+                            </span>
+                            <span>{{ user.username }}</span>
+                        </a>
+                        <ul class="dropdown-menu dropdown-menu-end">
+                            <li>
+                                <a class="dropdown-item" href="{% url 'settings' %}">账户设置</a>
+                            </li>
+                            <li>
+                                <form action="{% url 'logout' %}" method="post" class="w-100">
+                                    {% csrf_token %}
+                                    <button type="submit" class="dropdown-item">登出</button>
+                                </form>
+                            </li>
+                        </ul>
+                    </div>
+                    {% endif %}
+                </div>
             </div>
-        </div>
-    </nav>
+        </nav>
+    </header>
 
-    <div class="container mt-4">
+    <main class="container mt-4">
         {% block content %}{% endblock %}
-    </div>
+    </main>
 
     <footer class="text-center text-lg-start mt-auto">
         <div class="text-center p-3">
diff --git a/forum/templates/forum/index.html b/forum/templates/forum/index.html
index 8df4fe1..82c370e 100644
--- a/forum/templates/forum/index.html
+++ b/forum/templates/forum/index.html
@@ -13,7 +13,7 @@ <h1>可打分的项目</h1>
     <div class="card" style="width: 18rem;">
       <div class="card-body">
         <h5 class="card-title">{{ item.name }} - 平均分：{{ item.average_rating|floatformat:1 }}</h5>
-        <a href="{% url 'rate_item' item.id %}" class="btn btn-primary">去打分</a>
+        <a href="{% url 'rate_item' item.id %}" class="btn btn-primary" aria-label="给{{ item.name }}打分">去打分</a>
       </div>
     </div>
   </div>
@@ -33,7 +33,7 @@ <h1>帖子</h1>
       <div class="card-body">
         <h5 class="card-title">{{ post.title }} - 作者：{{ post.author }}</h5>
         <p class="card-text">{{post.created_at | naturaltime}}</p>
-        <a href="{% url 'post_detail' post.id %}" class="btn btn-primary">去查看</a>
+        <a href="{% url 'post_detail' post.id %}" class="btn btn-primary" aria-label="查看{{ post.title }}">去查看</a>
       </div>
     </div>
   </div>
