change the behavior of curriculum overview

[dariah-eric]

change the behavior of curriculum overview

[stefanprobst]

make the overview stick with the text (at the moment if you scroll down to the last resource on the overview page, you will lose the overview links)

that's just how css position: sticky works - when you scroll to the end, the footer will push the rest of the page up, including the sidebar and its sticky content.

[ttasovac]

@stefanprobst I've merged #123. would it also be possible to

highlight the links in the overview as the users scrolls down the page and reaches individual titles and abstracts — to mimic the behavior of the table of contents.

(this will be especially useful when we have 20 courses in a curriculum, like for ELEXIS)

[stefanprobst]

highlight the links in the overview as the users scrolls down the page and reaches individual titles and abstracts — to mimic the behavior of the table of contents.

true, sorry forgot about that - yes let's add this