content_text_30px_fontSize_1_lines_container_width_unknown_height_unknown_center_middle_IE_minVer_10.txt

<div id="container">
  <div id="middle">
    <div id="content">I</div>
  </div>
</div>

#parent {
display: table;
}

#middle {
display: table-cell;
vertical-align: middle;
}

#child {
font-size: 30px;
height: 30px;
text-align: center;
}