{{- $code := .Get 0 | lower -}}
{{- $validCodes := slice "de" "en" "deen" -}}
{{- if not (in $validCodes $code) -}}
  <span style="color: red; font-weight: bold;">Warning: Invalid or missing language code '{{ $code }}'. Use 'de', 'en', or 'deen'.</span>
{{- else -}}
  {{- $label := cond (eq $code "de") "DE" (cond (eq $code "en") "EN" (cond (eq $code "deen") "DE/EN" "")) -}}
  {{- $title := "" -}}
  {{- if eq $code "deen" -}}
      {{- $title = cond (eq .Site.Language.Lang "de") "Diese Tour wird zweisprachig stattfinden (Deutsch und Englisch)" "This tour will be bilingual (German and English)" -}}
  {{- else if eq $code "de" -}}
      {{- $title = cond (eq .Site.Language.Lang "de") "Diese Tour wird auf Deutsch stattfinden" "This tour will be held in German" -}}
  {{- else if eq $code "en" -}}
      {{- $title = cond (eq .Site.Language.Lang "de") "Diese Tour wird auf Englisch stattfinden" "This tour will be held in English" -}}
  {{- end -}}
  <abbr style="font-size: .65em; vertical-align: super;" title="{{ $title }}">{{ $label }}</abbr>
{{- end -}}