Hi Jean,

Under the Admin menu, you can change the default Portal Skin and Container. It's under the "Basic Settings" tab, under the "Appearance" section.

If you are looking to change the skin for the sample pages you see upon a clean install, unfortunately you will have to go to each of those pages and change them manually, as they are specifically set to the Dark Knight skin.  If you want to test other skins on these pages without constantly having to revisit each page and setting the skin, you can just set them to the Portal Default.

If you've changed the Portal default skin and container, new pages you create will have your custom skin applied rather than the Dark Knight skin.

-- vince.