div#tracks
  = form.simple_fields_for :tracks do |ff|
    .col-lg-6
      .panel.panel-default
        .panel-body
          = ff.input :name
          = ff.input :color, as: :color
          = ff.input :description
        .panel-footer.text-right
          = ff.link_to_remove t('helpers.destroy', model: Track.model_name.human), class: ['btn', 'btn-danger', ff.object.events.any? ? 'disabled' : nil]
.col-lg-6
  .panel.panel-default
    .panel-body.text-right
      = form.link_to_add t('helpers.submit.create', model: Track.model_name.human), :tracks, data: {target: '#tracks'}, class: 'btn btn-success'