adjust styling and bump dates etc

layouts/datengarten/section.ics

@@ -21,6 +21,7 @@ END:STANDARD
 END:VTIMEZONE
 
 {{ range .Pages }}
+{{ if and .Params.event.start .Params.event.end -}}
 BEGIN:VEVENT
 ORGANIZER;CN="CCCB":mailto:datengarten@berlin.ccc.de
 SUMMARY:{{ .Title }}{{ with .Params.subtitle }}: {{ . }}{{ end }}
@@ -34,5 +35,6 @@ LOCATION:{{ with .Params.location }}{{ . }}{{ else }}CCCB{{ end }}
 URL:{{ .Permalink }}
 DESCRIPTION:{{ .Permalink }}
 END:VEVENT
+{{ end -}}
 {{ end }}
 END:VCALENDAR