title: Firefox text 1px lower than chrome and ie
body: <p>This is driving me crazy. Firefox text is 1px lower than in chrome and ie. It's not a margin or padding issue on html or body, tried that. Doesn't seem to be a rounding issue either. Here is an image:</p>
  
  <p><img src="https://i.stack.imgur.com/B4Tei.png" alt="enter image description here"></p>
  
  <p>First "Hello" is Firefox 13, Second "Hello" is IE9 and "Hello World" is Chrome.</p>
  
  <p>Here is the code (pretty simple):</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html lang="en-us"&gt;
      &lt;head&gt;
          &lt;meta charset="utf-8"&gt;
          &lt;!-- Always force latest IE rendering engine and chrome frame --&gt;
          &lt;meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"&gt;
          &lt;title&gt;Pixel Bug?&lt;/title&gt;
      &lt;style type="text/css"&gt;
          html{
              font-size: 100%;
          }
          body{
              font-size: 1em;
              line-height: 1.5;
              background: white url('images/grid16.png') -4px -6px;
          }
          p{
              margin: 1.5em 0;
          }
      &lt;/style&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;p&gt;Hello World!&lt;/p&gt;
      &lt;p&gt;Hello World 2!&lt;/p&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>Is it just a bug? What is going on here? I don't want a FireFox only work around, I just want to understand why this is happening.</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Upon further research it seems to be a rendering bug, but it still confuses me. For example, the height of the text should be 24px. Which shouldn't really cause rounding errors that would cause this. Yet, if I change the line-height to 23px explicitly it lines up. I have no idea why.</p>
  
  <p><strong>EDIT2:</strong> Possible reason? <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=442139" rel="noreferrer">https://bugzilla.mozilla.org/show_bug.cgi?id=442139</a></p>
  
  <p><strong>EDIT3:</strong> Lines up using a 20px font and 40px line height. Makes me think this is just so rendering bug. It's sucks cause 16/24 is pretty standard :/</p>