Merge branch '18533-graphs-wiki-subnav' into 'master'

Resolve "Graphs and Wiki subnav"

## What does this MR do?
Styles sub nav in `Wiki` and `Graphs`

## What are the relevant issue numbers?
Closes #18533 

## Screenshots (if relevant)
![Screen_Shot_2016-06-15_at_9.32.43_AM](/uploads/111dae6e1b9c7d8038ac88b9be6f76a2/Screen_Shot_2016-06-15_at_9.32.43_AM.png)

cc @dzaporozhets 

See merge request !4678