Uses antora supplemental_files to customize UI

Antora supplemental_files are not well documented but they allow to
override the UI templates from the UI bundle, not that this mecanisme
DOES NOT allow properly overriding UI style, only content and HTML
structure.
diff --git a/.gitignore b/.gitignore
index c81bc51..1d5f4c1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,8 +4,12 @@
 # Ignore Gradle build output directory
 build
 
+
+# Ignore antora cache directorry
+doc-sites/.cache
+
 .vscode
 .project
 
 node_modules
-target
\ No newline at end of file
+target
diff --git a/doc-sites/antora-playbook-local.yml b/doc-sites/antora-playbook-local.yml
index 719c089..96e332b 100644
--- a/doc-sites/antora-playbook-local.yml
+++ b/doc-sites/antora-playbook-local.yml
@@ -8,33 +8,15 @@
   start_page: james-site::homepage.adoc
 content:
   sources:
-  - url: ./../../james-hupa
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-jdkim
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-jsieve
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-jspf
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-mime4j
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-project
-    branches: HEAD
-    start_path: docs
-  - url: ./../../james-postage
-    branches: HEAD
-    start_path: docs
-  - url: ./../
-    branches: HEAD
-    start_path: docs
+    - url: ./../../james-project
+      branches: HEAD
+      start_path: docs
+    - url: ./../
+      branches: HEAD
+      start_path: docs
 ui:
   bundle:
-    url: ./../antora-ui/build/ui-bundle.zip
-    # start_path: ui-bundle
+    url: https://gitlab.com/antora/antora-ui-default/-/jobs/artifacts/master/raw/build/ui-bundle.zip?job=bundle-stable
+  supplemental_files: ./ui-overrides
 runtime:
   fetch: true
diff --git a/doc-sites/antora-playbook.yml b/doc-sites/antora-playbook.yml
index 75a6900..ea115e8 100644
--- a/doc-sites/antora-playbook.yml
+++ b/doc-sites/antora-playbook.yml
@@ -1,44 +1,21 @@
+runtime:
+  cache_dir: ./.cache/antora
+  fetch: true
 site:
   title: Apache James
   url: https://james.apache.org/
   start_page: james-site::homepage.adoc
 content:
   sources:
-  - url: https://github.com/apache/james-hupa.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-jdkim.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-jsieve.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-jspf.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-mime4j.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-project.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: https://github.com/apache/james-postage.git
-    branches: master
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
-  - url: ./../
-    branches: HEAD
-    start_path: docs
-    edit_url: '{web_url}/blob/{refname}/{path}'
+    - url: https://github.com/apache/james-project.git
+      branches: master
+      start_path: docs
+      edit_url: "{web_url}/blob/{refname}/{path}"
+    - url: ./../
+      branches: HEAD
+      start_path: docs
+      edit_url: "{web_url}/blob/{refname}/{path}"
 ui:
   bundle:
-    url: ./../antora-ui/build/ui-bundle.zip
-    # start_path: ui-bundle
-runtime:
-  fetch: true
+    url: https://gitlab.com/antora/antora-ui-default/-/jobs/artifacts/master/raw/build/ui-bundle.zip?job=bundle-stable
+  supplemental_files: ./ui-overrides
diff --git a/doc-sites/ui-overrides/img/james.svg b/doc-sites/ui-overrides/img/james.svg
new file mode 100644
index 0000000..cdab29b
--- /dev/null
+++ b/doc-sites/ui-overrides/img/james.svg
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Generator: Adobe Illustrator 15.0.0, SVG Export Plug-In . SVG Version: 6.00 Build 0)  -->
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg version="1.1" id="Calque_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+	 width="37px" height="31px" viewBox="0 0 37 31" enable-background="new 0 0 37 31" xml:space="preserve">
+<g>
+	<path fill="#FFFFFF" d="M37.001,4.407c-1.435-0.966-2.92-1.75-4.473-2.153c-1.552-0.412-3.151-0.315-4.63,0.3l-0.277,0.117
+		l-0.139,0.062l-0.064,0.032l-0.036,0.016l-0.018,0.008l-0.008,0.004c0.008-0.007-0.028,0.016,0.02-0.012L27.37,2.783
+		c-0.2,0.127-0.391,0.232-0.589,0.337c-0.392,0.207-0.796,0.391-1.216,0.543c-0.836,0.295-1.737,0.503-2.664,0.389
+		c-0.458-0.061-0.913-0.222-1.3-0.489c-0.382-0.268-0.689-0.629-0.899-1.026C20.28,1.737,20.15,0.857,20.124,0
+		c0.156,0.842,0.393,1.686,0.857,2.363c0.234,0.336,0.523,0.622,0.864,0.811c0.339,0.19,0.723,0.284,1.111,0.301
+		c0.782,0.038,1.582-0.201,2.325-0.532c0.376-0.165,0.741-0.353,1.092-0.563c0.176-0.105,0.354-0.219,0.509-0.33l0.307-0.201
+		c0.1-0.057,0.194-0.122,0.293-0.173c0.801-0.433,1.702-0.731,2.627-0.793c0.925-0.069,1.856,0.063,2.716,0.357
+		c0.863,0.29,1.655,0.731,2.359,1.267C35.888,3.047,36.52,3.676,37.001,4.407z"/>
+	<path fill="#FFFFFF" d="M13.25,20.418c-5.733-4.373-9.554-8.973-9.418-9.078c0.147-0.145,4.153,4.212,9.83,8.536
+		c1.665,1.28,3.28,2.412,4.733,3.381c0.02-0.036,0.041-0.069,0.062-0.105c0.237-0.456,0.42-0.948,0.562-1.462
+		c-1.018-2.053-3.554-4.892-6.501-7.496c-0.656-0.572-1.338-1.078-2.028-1.536c-0.151,1.223-0.452,2.098-0.453,2.096
+		c0,0-0.335-1.163-0.306-2.579C9.266,11.892,8.8,11.63,8.336,11.389c-0.004,1.395-0.414,2.439-0.417,2.439
+		c0,0.002-0.833-1.414-0.922-3.071c-0.002-0.01-0.002-0.021-0.002-0.031c-2.767-1.279-5.1-1.896-5.104-1.89
+		C1.867,8.774,2.064,14.75,6.431,19.305c0.147-0.008,0.296-0.016,0.449-0.016c1.588,0.004,2.944,0.577,2.947,0.577
+		c0-0.002-0.835,0.501-2.054,0.671c0.444,0.355,0.899,0.682,1.364,0.973c1.148-0.416,2.102-0.557,2.102-0.557
+		c0-0.002-0.503,0.495-1.334,1.017c3.035,1.685,5.787,2.542,7.53,2.624c0.236-0.26,0.452-0.532,0.645-0.821
+		C16.586,22.84,14.938,21.717,13.25,20.418z"/>
+	<path fill="#FFFFFF" d="M33.7,4.335c-1.103,0.092-2.21,0.292-3.3,0.605c-2.173,0.623-4.31,1.725-6.062,3.396
+		c-0.883,0.824-1.64,1.798-2.271,2.846c-0.614,1.059-1.109,2.191-1.43,3.363c-0.327,1.168-0.529,2.363-0.595,3.548
+		c-0.02,0.291-0.031,0.596-0.039,0.9L19.995,19.4l-0.008,0.35c-0.012,0.462-0.051,0.918-0.122,1.358
+		c-0.056,0.337-0.131,0.665-0.223,0.984c-0.141,0.514-0.324,1.006-0.562,1.466c-0.02,0.036-0.043,0.066-0.062,0.102
+		c-0.099,0.178-0.204,0.353-0.317,0.52c-0.191,0.286-0.407,0.559-0.643,0.819c-0.17,0.186-0.348,0.366-0.544,0.541
+		c-1.304,1.152-3.097,1.944-5.021,2.453c-1.931,0.518-3.995,0.788-6.091,0.934c-2.1,0.145-4.234,0.166-6.404,0.112
+		c2.023,0.815,4.157,1.338,6.333,1.664c2.179,0.313,4.422,0.415,6.701,0.127c1.137-0.149,2.287-0.394,3.418-0.802
+		c1.129-0.405,2.252-0.959,3.265-1.745c1.019-0.771,1.92-1.77,2.571-2.913c0.331-0.568,0.601-1.167,0.82-1.775
+		c0.21-0.611,0.364-1.236,0.47-1.859c0.11-0.619,0.17-1.24,0.193-1.852c0.008-0.154,0.008-0.307,0.008-0.461v-0.398
+		c0.005-0.234,0.011-0.468,0.022-0.716c0.052-0.967,0.166-1.914,0.376-2.832c0.418-1.832,1.213-3.537,2.405-5.009
+		c1.192-1.472,2.767-2.711,4.552-3.706c1.79-0.994,3.765-1.774,5.862-2.355C35.917,4.247,34.808,4.238,33.7,4.335z"/>
+</g>
+</svg>
diff --git a/doc-sites/ui-overrides/partials/header-content.hbs b/doc-sites/ui-overrides/partials/header-content.hbs
new file mode 100644
index 0000000..caa1c0b
--- /dev/null
+++ b/doc-sites/ui-overrides/partials/header-content.hbs
@@ -0,0 +1,52 @@
+<header class="header">
+  <nav class="navbar">
+    <div class="navbar-brand">
+      <a class="navbar-item" href="{{{or site.url (or siteRootUrl siteRootPath)}}}"><img src="/_/img/james.svg" alt="james logo"> {{site.title}}</a>
+      <button class="navbar-burger" data-target="topbar-nav">
+        <span></span>
+        <span></span>
+        <span></span>
+      </button>
+    </div>
+    <div id="topbar-nav" class="navbar-menu">
+      <div class="navbar-end">
+        <a class="navbar-item" href="#">Home</a>
+        <div class="navbar-item has-dropdown is-hoverable">
+          <a class="navbar-link" href="#">Products</a>
+          <div class="navbar-dropdown">
+            <div class="navbar-item"><strong>James server</strong></div>
+            <a class="navbar-item" href="https://github.com/apache/james-project">Repository</a>
+            <a class="navbar-item" href="https://issues.apache.org/jira/projects/JAMES/issues">Issue Tracker</a>
+            <hr class="navbar-divider">
+            <a class="navbar-item" href="https://james.apache.org/mime4j/index.html">Mime4J</a>
+            <a class="navbar-item" href="https://james.apache.org/jsieve/index.html">jSieve</a>
+            <a class="navbar-item" href="https://james.apache.org/jspf/index.html">jSPF</a>
+            <a class="navbar-item" href="https://james.apache.org/jdkim/index.html">jDKIM</a>
+            <a class="navbar-item" href="https://james.apache.org/hupa/index.html">HUPA</a>
+          </div>
+        </div>
+        <div class="navbar-item has-dropdown is-hoverable">
+          <a class="navbar-link" href="#">Community</a>
+          <div class="navbar-dropdown">
+             <!-- Not ideal but dropping the version in the href requires tweaking james-projet docs module first -->
+            <a class="navbar-item" href="/james-project/3.6.0/community/mailing-lists.html">Mailing lists</a>
+            <a class="navbar-item" href="https://gitter.im/apache/james-project"><svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 32 32" class="logo-gitter-sign" data-v-44ebcb1a=""><rect x="15" y="5" width="2" height="10"></rect> <rect x="10" y="5" width="2" height="20"></rect> <rect x="5" y="5" width="2" height="20"></rect> <rect width="2" height="15"></rect></svg> Gitter</a>
+            <a class="navbar-item" href="https://twitter.com/ApacheJames">
+              <span class="icon">
+                <svg aria-hidden="true" data-icon="twitter" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
+                  <path fill="#57aaee" d="M459.37 151.716c.325 4.548.325 9.097.325 13.645 0 138.72-105.583 298.558-298.558 298.558-59.452 0-114.68-17.219-161.137-47.106 8.447.974 16.568 1.299 25.34 1.299 49.055 0 94.213-16.568 130.274-44.832-46.132-.975-84.792-31.188-98.112-72.772 6.498.974 12.995 1.624 19.818 1.624 9.421 0 18.843-1.3 27.614-3.573-48.081-9.747-84.143-51.98-84.143-102.985v-1.299c13.969 7.797 30.214 12.67 47.431 13.319-28.264-18.843-46.781-51.005-46.781-87.391 0-19.492 5.197-37.36 14.294-52.954 51.655 63.675 129.3 105.258 216.365 109.807-1.624-7.797-2.599-15.918-2.599-24.04 0-57.828 46.782-104.934 104.934-104.934 30.213 0 57.502 12.67 76.67 33.137 23.715-4.548 46.456-13.32 66.599-25.34-7.798 24.366-24.366 44.833-46.132 57.827 21.117-2.273 41.584-8.122 60.426-16.243-14.292 20.791-32.161 39.308-52.628 54.253z"></path>
+                </svg>
+              </span> Twitter
+            </a>            
+            <a class="navbar-item" href="#">  <svg class="octicon octicon-mark-github v-align-middle" viewBox="0 0 16 16" version="1.1" aria-hidden="true"><path fill-rule="evenodd" d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.013 8.013 0 0016 8c0-4.42-3.58-8-8-8z"></path></svg> Github</a>
+          </div>
+        </div>
+<!--        <div class="navbar-item">
+          <span class="control">
+            <a class="button is-primary" href="#">Download</a>
+          </span>
+        </div> -->
+      </div>
+    </div>
+  </nav>
+</header>