Adaptive Form Theme Editor - Stretch to fit page content

By default, the adaptive form page content is centered and is not set to adjust to the width of the browser.

In the theme editor, how do you make it so the page content is left adjusted, with the content stretched to fit to the width of the browser? I changed the setting of the Page to float:left, but the content of the form is not stretch to fit to the browser.  Please see below image for clarification.