title: Html/Css my html doesn't work with my header
body: <p>I have 2 files. The first is my content and the second is my header (on the left).</p>
  <p>When i use my new header my html disappears.</p>
  <p>There is my html/css header:</p>
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang=&quot;en&quot;&gt;
  &lt;head&gt;
      &lt;style&gt;
          @import url('https://fonts.googleapis.com/css?family=Josefin+Sans&amp;display=swap');
  
  *{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    list-style: none;
    text-decoration: none;
    font-family: 'Josefin Sans', sans-serif;
  }
  
  .wrapper{
    display: flex;
    position: relative;
  }
  
  .wrapper .sidebar{
    width: 15%;
    height: 100%;
    background: #080808;
    position: fixed;
  }
  
  .wrapper .sidebar h2{
    color: #fff;
    text-transform: uppercase;
    text-align: center;
    margin-bottom: 30px;
  }
  
  .wrapper .sidebar ul li{
    padding: 28px;
    border-bottom: 1px solid #2a00fa;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    border-top: 1px solid rgba(255,255,255,0.05);
  }    
  
  .wrapper .sidebar ul li a{
    color: #bdb8d7;
    display: block;
  }
  
  .wrapper .sidebar ul li a .fas{
    width: 25px;
  }
  
  .wrapper .sidebar ul li:hover{
    background-color: #594f8d;
  }
      
  .wrapper .sidebar ul li:hover a{
    color: #fff;
  }
   
  
  
  .wrapper .main_content{
    width: 100%;
    margin-left: 200px;
  }
  
  
  
      &lt;/style&gt;
      &lt;meta charset=&quot;UTF-8&quot;&gt;
      &lt;title&gt;Side Navigation Bar&lt;/title&gt;
      &lt;link rel=&quot;stylesheet&quot; href=&quot;styles.css&quot;&gt;
      &lt;script src=&quot;https://kit.fontawesome.com/b99e675b6e.js&quot;&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  
  &lt;div class=&quot;wrapper&quot;&gt;
      &lt;div class=&quot;sidebar&quot;&gt;
      &lt;img src=&quot;https://www.cfnews.net/var/cfnews/storage/images/mediatheque/hd/standard-hd/logos/equitim-art-logo-2019/9643799-1-fre-FR/Equitim-ART-logo-2019.jpg&quot; width=&quot;100%&quot; height=&quot;25%&quot; alt=&quot;me&quot;&gt;
  
  
  
  
          &lt;div style='margin-top:29%'&gt;
          &lt;ul&gt;
              &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&lt;i class=&quot;fas fa-home&quot;&gt;&lt;/i&gt; Dashboard&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&lt;i class=&quot;fas fa-file&quot;&gt;&lt;/i&gt;Templates&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&lt;i class=&quot;fas fa-solid fa-folder-plus&quot;&gt;&lt;/i&gt;New Template&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href=&quot;#&quot;&gt;&lt;i class=&quot;fas fa-solid fa-chart-line&quot;&gt;&lt;/i&gt;sous-jacents&lt;/a&gt;&lt;/li&gt;
              &lt;li&gt;&lt;a href=&quot;creer-sous-jacent&quot;&gt;&lt;i class=&quot;fas fa-thin fa-filter&quot;&gt;&lt;/i&gt;New Sous-jacent&lt;/a&gt;&lt;/li&gt;
          &lt;/ul&gt; 
        &lt;/div&gt;
      
      &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  <p>And there is my simple second html function:</p>
  <pre><code>{% extends &quot;new_layout.html&quot; %}
  {% block content %}
  
  &lt;div&gt;
       &lt;div style=&quot;left: 100%; background-color: red;&quot;&gt;
            AJUIJOIASAJISOOISAJASIASOAJSOIASJOIASJOIASJOIASJOIAJSOIAJSOIAS
       &lt;/div&gt;
       creation sous-jacents
       &lt;form action=&quot;creer-sous-jacent&quot;, method=&quot;post&quot;&gt;
            &lt;div&gt;
                 libellé
                 &lt;input type=&quot;text&quot; id=&quot;libelle&quot; name=&quot;libelle&quot;    required=&quot;required&quot;&gt; 
            &lt;/div&gt;
  
            &lt;div&gt;
                 Ticker
                 &lt;input type=&quot;text&quot; id=&quot;&quot;ticker name=&quot;ticker&quot; required=&quot;required&quot;&gt;
            &lt;/div&gt;
            &lt;div&gt;
                 &lt;p&gt;&lt;input type=&quot;submit&quot; value=&quot;submit&quot;&gt;&lt;/p&gt;
               &lt;/div&gt;
       &lt;/form&gt;
  
  
  &lt;/div&gt;
  
  
  
  {% endblock %}
  </code></pre>
  <p>I don't have any problem when i use my old template. I tried to put on the right the content, to put new text but nothing works. I removed all the style in my header but it doesn't work.</p>
  <p>If someone has the solution.</p>
  <p>Thanks for your reading</p>