Source code of Demo page

<style>

:first-letter {
font-size: 2em;
padding-left: 1em;
}

div { margin: 0.5em 2em; border: 1px solid }

</style>

<h1>::first-letter</h1>

<div>
test
</div>

<div>
<div>
test
</div>
</div>

<div>
<div>
<div>
test
</div>
</div>
</div>

Result in Chrome 20

Result in IE 10.0.8250.0