navigation.rb

SimpleNavigation::Configuration.run do |navigation|
  navigation.renderer = MaterializeRenderer
  navigation.auto_highlight = false

  navigation.items do |primary|
    primary.item   :book_header, '[Book]',   '#'            do |sub_nav|
      sub_nav.item :books,       'Books',    books_path,    highlights_on: hl(:books)
      sub_nav.item :new_book,    'New Book', new_book_path, highlights_on: hl(:new_book)
    end
    primary.item   :welcome,     'Welcome',  root_path,     highlights_on: hl(:welcome)
  end
end