If the introduction is opened in landscape, the text is not visible.

We have to add a new layout for the fragment, for the case of landscape mode, putting the text beside the image (maybe rescaling it?).

The first part is easy, the rescaling probably not so much. Anyway, it should not be difficult. The new layout has to be put in the appropriate folder (layout-landscape ?).

Thanks @valerio.bozzolan for raising the issue

See D219 for screenshot