title: CSS Negative margins for positioning
body: <p>Is it ok to use negative margins for positioning? I have a lot in my current site and feel like it's not such a stable way to position things. I usually suggest to use them too. </p>
  
  <p>For example I have a checkout page with three divs on top of each other </p>
  
  <pre><code>&lt;div class="A"&gt;
     header
  &lt;/div&gt;
  &lt;div class="B"&gt;
     content
  &lt;/div&gt;
  &lt;div class="C"&gt;
     footer
  &lt;/div&gt;
  </code></pre>
  
  <p>(A, B and C), which are meant to sit on top of each other, to appear attached. I did this using: </p>
  
  <pre><code>.B
  {
      margin-top: -20px;
  }
  </code></pre>
  
  <p>On div B, to meet the bottom of div A.</p>
  
  <p>Is this good practice or shall I re-code using <code>top</code> and <code>left</code>?</p>