Open a content file with eXeLearning 3 and export it in these formats: Website, Single page, SCORM 1.2. Do not change the default names that eXeLearning assigns (they end with _page.zip, _scorm.zip, and _web.zip).
Select the three .zip files and click on "Upload and process."
When the process is finished, go back to "Style Designer" to preview the different views.
You can edit the theme files and see the changes reflected immediately.