module Jekyll
  class ProofTagBlock < Liquid::Block

    def render(context)
      text = super
      "<span style=\"text-transform: uppercase; font-weight: bold; font-size: .75em;\">Proof</span> #{text} <span style=\"float:right;\">$\\square\\enspace$</span>"
    end

  end
end

Liquid::Template.register_tag('proof', Jekyll::ProofTagBlock)