rohanverma.net/themes/after-dark/layouts/partials/components/formgroup.html

<fieldset
  {{ with .form }}form="{{ . }}" {{ end }}
  {{ with .name }}name="{{ . }}" {{ end }}
  {{ if eq .disabled "true" }}disabled {{ end }}
  class="form-group{{ if eq .hastextarea "true" }} form-textarea{{ end }}{{ if in (slice "success" "error" "warning") .state }} form-{{ .state }}{{ end }}{{ with .class }} {{ . }}{{ end }}">
  {{ with .legend }}<legend>{{ . }}</legend>{{ end }}
  {{ .body }}
</fieldset>