I added Template:Gravid_About to include a page, and included them through iframe in a normal html page: TestPage.html. The result is not as expected, the inclusion still shows header and footer. I had expected to see only the text
I have now tested in Opera, Vivaldi, Chrome, and Safari.
All of them have the header with them.
Mac OS issue? - I can't believe that the OS affects the view in the browser.
Have I forgotten something in the Wiki as packages?
Something really weird going on here! On my Linux and Windows systems I do not see the header. I was suspicious that Opera may have been ignoring the CSS, but would not expect WebKit based browsers to.
However, I've just tested on a borrowed Air and the header is showing as you say. I'll have to further investigate. It must be something to do with the way WebKit handles iFrames. Unfortunately differences between browser engines are all to common :(
Okay, something really odd going on here. It works if you are logged into the CWI site. But if you are not logged in, the CSS is ignored and you see the header etc. Never seen that before! It must be something to do with the skin.