This is an em-based layout

In some browsers, this layout will "zoom" dead center and part of the content will end up off screen, to the left of the viewport.

Check this page with the fix applied.

Markup

<body>
  <div>
    <h1>This is an em-based layout</h1>
    <h2>Markup</h2>
    blah blah
    <h2>CSS</h2>
    blah blah
  </div>
</body>

div {margin:0 auto;width:34em;}