From what I can see so far there is a pre-defined font causing the text to start off as "Open Sans", but then it enlarges once the CSS loads.
<style type="text/css">
html > body {font-family: Open Sans;}
h1, h2, h3, h4, h5, h6, blockquote {font-family: Droid Serif}
#navwrap li {font-family: sans-serif}
#logo a{font-family: Droid Serif;
}
{font-family:;}
</style>