<div class="vertical-align-all-child-elements">
text with really small size
<span class="one-line">oneline</span>
<span class="two-line">two line content</span>
<span class="one-line-width-tall-height">oneline tall height</span>
As in <a href="http://www.w3.org/TR/CSS21/visudet.html#propdef-vertical-align">W3C Vertical Align</a>, the <span class="quote">vertical-align:middle</span> is rendered as <span class="quote">Align the vertical midpoint of the box with the baseline of the parent box plus half the x-height of the parent.</span>. So to vertical align all the child elements (with various height), we set the font-size of the parent element to be very small until the <span class="quote">the difference between x-height and font-size is really small</span>.