Import highlight.js style inline.

We can minify with the rest of the generated CSS this way and let bower
handle the .css file we use.
Logical to nest this.
Remove unnecessary flex.
Correct weird off-centreness.
Add subtle menu.

Archive and about pages tbd… :)
Fix indentation.
Make fleuron a directive.
Separate out articles resolver code.
Remove unnecessary show-header functionality.
Add about and archive

So the menu has some pages to point at ;)