Tidy styles for community section

This change enables an opt-in switch to new styles for /community
It is opt-in to enable localizations to migrate to the new page on their
own timeline.

layouts/partials/head.html

@@ -92,6 +92,14 @@
 <script async src="{{ "js/mermaid.min.js" | relURL }}"></script>
 {{ end }}
 
+{{- if eq (lower .Params.cid) "community" -}}
+{{- if eq .Params.community_styles_migrated true -}}
+<link href="/css/community.css" rel="stylesheet"><!-- legacy styles -->
+{{- else -}}
+<link href="/css/legacy_community.css" rel="stylesheet">
+{{- end -}}
+<script defer src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
+{{- end -}}
 <script src="{{ "js/script.js" | relURL }}"></script>
 {{ with .Params.js }}{{ range (split . ",") }}<script src="{{ (trim . " ") | relURL }}"></script><!-- custom js added -->
 {{ end }}{{ else }}<!-- no custom js detected -->{{ end }}