Builder Responsive: Introduction
Starting with version 4.0, Builder is responsive. This means Builder will automatically adjust pages for mobile and tablet viewing.
Issues with IE
Unfortunately, responsive sites don't work very well on Internet Explorer < 9. That being the case, our themes have rules for IE 6, 7, and 8 that keep the site full width. This may not be ideal, but it is certainly much better than having a terrible-looking site in IE < 9.