title: Issue trying to customizing the admin in Django
body: <p>In order to add some links in the admin of my site I added a custom block (surrounded in red in the images below) to admin/base.html and set it in admin/base_site.html.</p>
  
  <p>The issue is that it's shown in all admin pages (eg connexion screenshot shown below), while I'd like to show it only in the site admin first page.</p>
  
  <p>Anybody could help?</p>
  
  <p><b>admin/base.html</b></p>
  
  <pre><code>...
  
  &lt;!-- Content --&gt;
  &lt;div id="content" class="{% block coltype %}colM{% endblock %}"&gt;
      {% block pretitle %}{% endblock %}
      {% block content_title %}{% if title %}&lt;h1&gt;{{ title }}&lt;/h1&gt;{% endif %}{% endblock %}
      {% block content %}
      {% block object-tools %}{% endblock %}
      {{ content }}
      {% endblock %}
      {% block sidebar %}{% endblock %}
  
      {% block myblock %}{% endblock %} &lt;!-- custom block --&gt;
  
      &lt;br class="clear" /&gt;
  &lt;/div&gt;
  &lt;!-- END Content --&gt;
  
  ....
  </code></pre>
  
  <p><b>admin/base_site.html</b></p>
  
  <pre><code>....
  
  {% extends "admin/base.html" %}
  {% load i18n %}
  
  {% block title %}{{ title }} | {% trans 'Django site admin' %}{% endblock %}
  
  {% block branding %}
  &lt;h1 id="site-name"&gt;{% trans 'Administration de Django' %}&lt;/h1&gt;
  {% endblock %}
  
  {% block nav-global %}{% endblock %}
  {% block myblock %}
      &lt;div style="margin-top:160px;"&gt;
      &lt;div style="font-size:18px; color:#666666;font-weight:bold;margin-bottom:10px;"&gt;Rapports&lt;/div&gt;
          &lt;a href="/rapports_journaliers/"&gt;Rapports journaliers&lt;/a&gt;&lt;br/&gt;
          &lt;a href="/rapports_mensuels/"&gt;Rapports mensuels&lt;/a&gt;
      &lt;/div&gt;
  {% endblock %}
  
  ....
  </code></pre>
  
  <p><b>Site admin</b></p>
  
  <p><img src="https://i.stack.imgur.com/vTxog.png" alt="enter image description here"></p>
  
  <p><b>Connexion</b></p>
  
  <p><img src="https://i.stack.imgur.com/i48F1.png" alt="enter image description here"></p>