How do I override default formatting for a>img in the header?

How do I override default formatting for a>img in the header?

Per  http://jquerymobile.com/demos/1.0a2/#docs/toolbars/docs-headers.html, I wrapped the header content in another div to stop the default formatting. This seems to have worked on div[data-role=header]>div>h1 (not centering it), but it didn't work on div[data-role=header]>div>div>a, which still is rendered button-style.

It seems to be more involved than a simple style. The script puts the link contents into a span and nests it a couple layers down. Please advise on what might be the best way to prevent header-style formatting from being applied to these links.