Update the content header partial

layouts/partials/content_header.html

@@ -1,9 +1,12 @@
-<header>
-  <h1>{{ .Title }}</h1>
+<header class="content-title">
+  <h1>{{ .Title | markdownify }}</h1>
+  {{ with .Description -}}
+    <p class="subtitle">{{ . }}</p>
+  {{- end }}
 
-  {{ if and (not (eq .Section "about")) .Date }}
-    <time>{{ .Date | time.Format "January 2, 2006" }}</time>
-  {{ end }}
+  {{ with .Date -}} 
+    <time>{{ . | time.Format "January 2, 2006" }}</time>
+  {{- end }}
 
   {{- if .Params.series -}}
     {{- $series := .GetTerms "series" -}}