navigation.rb

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

  navigation.items do |primary|
    primary.item   :header1, 'Header1', '#'  do |sub_nav|
      sub_nav.item :item1,   'Item1',   '#', highlights_on: hl(:item1)
      sub_nav.item :item2,   'Item2',   '#', highlights_on: hl(:item2)
    end
    primary.item   :header2, 'Header2', '#', highlights_on: hl(:header2)
  end
end