Use 'div' instead of 'section' and 'article'

The user-agent stylesheet was making the size
of both the h1's and h2's 1.5em as it was inside
<article> and <section>

:-webkit-any(article,aside,nav,section)
h1 - 1.5em user agent stylesheet
~h1 - 2em~ user agent stylesheet

Change-Id: Ied1d03f63c132dc3904d05cd4e55f70aa3f80c3d