Top of the collapsible section. (Determine the position of the [Expand] link)
This is the part of the text that is displayed in any case. It can be, for instance, an abstract of the whole section or some kind of wrap-up or a teasing inviting the reader to expand the section to learn more.
Collapsible content.
This is the part of the text that is collapsible. It is usually the long portion of text that is detailing the concepts mentioned above, in the always displayed section.
(This part stretch as far as it reach the last template below:)