diff --git a/customizations/RaceCriticalTheories/layouts/partials/header.html b/customizations/RaceCriticalTheories/layouts/partials/header.html
new file mode 100644
index 0000000..38c7689
--- /dev/null
+++ b/customizations/RaceCriticalTheories/layouts/partials/header.html
@@ -0,0 +1,96 @@
+{{ $s := partialCached "scratch.html" . }}
+
+{{ $currentFile := (printf "/%s" .File) }}
+{{ $scratch := $s.Get $currentFile }}
+
+{{ $is_in_ := newScratch }}
+{{ with eq $scratch.depth "crust" }}
+ {{ range $scratch.is_in }}
+  {{ range $k,$v := $s.Get (printf "/%s" .File) }}
+   {{ if eq $k "is_in" }}
+     {{ range $v }}
+      {{ $is_in_.Set (printf "/%s" .File) (printf "/%s" .File)  }}
+    {{ end }}
+   {{ end }}
+  {{ end }}
+ {{ end }}
+{{ end }}
+
+{{ $is_in_is_in := (slice) }}
+{{ range $is_in_.Values }}
+  {{ $is_in_is_in = $is_in_is_in | append ($.GetPage .) }}
+{{ end }}
+
+{{ if eq hugo.Environment "preview" }}
+  {{- $giteaUrl := .Site.Params.sandpointsGiteaUrl -}}
+    <div class="headiter">
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}/_edit/master/content/{{ .File }}">EDIT_THIS</a>
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}/_new/master/content/{{ with $scratch.core }}{{ index . 0 }}{{ end }}/">ADD_{{ with $scratch.core }}{{ index . 0 | upper }}{{ end }}</a>
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}/_new/master/content/{{ with $scratch.mantle }}{{ index . 0 }}{{ end }}/">ADD_{{ with $scratch.mantle }}{{ index . 0 | upper }}{{ end }}</a>
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}/_new/master/content/{{ with $scratch.crust }}{{ index . 0 }}{{ end }}/">ADD_{{ with $scratch.crust }}{{ index . 0 | upper }}{{ end }}</a>
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}/_edit/master/PUBLISH.trigger.md">PUBLISH</a>
+        <a class="edit-button" target="_blank" href="{{ $giteaUrl }}"> ? </a>
+    </div>
+{{ end }}
+<p>*****************************************************</p>
+<div class="header">
+    <a title="{{ $.Site.Home.Title }}'s Bibliotheke" href="/library/BROWSE_LIBRARY.html" class="bibliotheke" target="_blank">
+        <img src="/images/bibliotheke.svg" />
+    </a>
+    <div class="breadcrumbs">
+        {{ if eq $scratch.depth "mantle" }}
+          {{ with gt (len $scratch.is_in) 1 }}
+            <div class="ddmenu">
+              <input id="toggly0" type="checkbox">
+              <label for="toggly0" tabindex="1"><span class="sup">cf.&nbsp;</span><a href="{{ with (index $scratch.is_in 0) }}{{ .RelPermalink }}{{ end }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ with index $scratch.is_in 0 }}<i>{{ .Title }}</i></a>&nbsp;{{ end }}</label>
+              <div class="hiddendiv">
+                <ul class="mt-4">
+                    {{ range after 1 $scratch.is_in }}
+                  <li><a href="{{ .RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}"><i>{{ .Title }}</i></a></li>
+                    {{ end }}
+                </ul>
+              </div>
+            </div>
+          {{ else }}
+            <a href="{{ with (index $scratch.is_in 0) }}{{ .RelPermalink }}{{ end }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}"><span class="sup">{{ with (index $scratch.is_in 0) }}{{ substr .Title 0 1  }}</span><i>{{ substr .Title 1 }}</i></a>{{ end }}
+          {{ end  }}
+            <span class="mantlebar"><i> » <a href="{{ .RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ .Title }}</a></i></span>
+        {{ end }}
+
+        {{ if eq $scratch.depth "crust" }}
+          {{ with gt (len $is_in_is_in) 1 }}
+            <div class="ddmenu">
+              <input id="toggly1" type="checkbox">
+              <label for="toggly1" tabindex="1"><span class="sup">cf.&nbsp;</span><a href="{{ with (index $is_in_is_in 0) }}{{ .RelPermalink }}{{ end }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ with (index $is_in_is_in 0) }}<i>{{ .Title }}</i></a>&nbsp;{{ end }}</label>
+              <div class="hiddendiv">
+                <ul class="mt-4">
+                    {{ range after 1 $is_in_is_in }}
+                  <li><a href="{{ .RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}"><i>{{ .Title }}</i></a></li>
+                    {{ end }}
+                </ul>
+              </div>
+            </div>
+          {{ else }}
+            {{ $home := index $is_in_is_in 0 }}
+            <a href="{{ $home.RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}"><span class="sup">{{ substr $home.Title 0 1  }}</span><i>{{ substr $home.Title 1 }}</i></a>
+          {{ end }}
+
+          {{ with gt (len $scratch.is_in) 1 }}
+            »&nbsp;
+            <div class="ddmenu">
+              <input id="toggly" type="checkbox">
+              <label for="toggly" tabindex="1"><span class="sup">cf.&nbsp;</span><a href="{{ with (index $scratch.is_in 0) }}{{ .RelPermalink }}{{ end }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ with (index $scratch.is_in 0) }}<i>{{ .Title }}</i></a>&nbsp;{{ end }}</label>
+              <div class="hiddendiv">
+                <ul class="mt-4">
+                    {{ range after 1 $scratch.is_in }}
+                  <li><a href="{{ .RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}"><i>{{ .Title }}</i></a></li>
+                    {{ end }}
+                </ul>
+              </div>
+            </div>
+          {{ else }}»&nbsp;<a href="{{ with (index $scratch.is_in 0) }}{{ .RelPermalink }}{{ end }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ with (index $scratch.is_in 0) }}<i>{{ .Title }}</i></a>{{ end }}
+          {{ end }}
+    <span class="mantlebar"><i> » <a href="{{ .RelPermalink }}{{ if eq hugo.Environment "offline" }}index.html{{ end }}">{{ .Title }}</a></i></span>
+    {{ end  }}
+    </div>
+</div>