Fix css on papers

[Libbum]

Particularly the abstract buttons, but in general we need new styling for everything here.

this branch will simplify the papers content once getzola/zola#249 closes, although that's waiting on a complete markdown refactor that could take some time.

A better solution would be to have a datafile that the template could read and populate from, but that's a feature that Gutenberg doesn't have (yet. I could look into that at some stage).

[Libbum]

Closed in 23d3eba