{{- $ratio := (split (.Get "ratio") ":") -}}
<div class="book-columns flex flex-wrap{{ with .Get "class" }} {{ . }}{{ end }}">
{{ range $index, $content := split .InnerDeindent "<--->" }}
  {{- $grow := default 1 (index $ratio $index) -}}
  <div class="flex-even markdown-inner" style="flex-grow: {{ $grow }};">
    {{ $content | safeHTML }}
  </div>
{{ end }}
</div>