diff --git a/_includes/head.html b/_includes/head.html
index f017f59..cc4d46b 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -72,7 +72,7 @@
   <!-- Font Awesome -->
   <link rel="stylesheet" href="{{ site.data.origin[type].fontawesome.css | relative_url }}">
 
-  <link rel="stylesheet" href="{{ '/assets/css/style.css' | relative_url }}">
+  <link rel="stylesheet" href="{{ '/assets/css/:THEME.css' | replace: ':THEME', site.theme | relative_url }}">
 
   {% if site.toc and page.toc %}
   <link rel="stylesheet" href="{{ site.data.origin[type].toc.css | relative_url }}">
diff --git a/_layouts/default.html b/_layouts/default.html
index 0854db1..4f35847 100644
--- a/_layouts/default.html
+++ b/_layouts/default.html
@@ -15,6 +15,10 @@ data-mode="{{ site.theme_mode }}"
 {% endif %}
 {% endcapture %}
 
+{% if layout.tail_includes %}
+  {% assign has_tail = true %}
+{% endif %}
+
 <!-- `site.alt_lang` can specify a language different from the UI -->
 <html lang="{{ site.alt_lang | default: site.lang }}" {{ prefer_mode }}>
 {% include head.html %}
@@ -31,36 +35,64 @@ data-mode="{{ site.theme_mode }}"
   {% include sidebar.html lang=lang %}
 
   <div id="main-wrapper" class="d-flex justify-content-center">
-    <div id="main" class="container px-xxl-5">
+    <div class="container px-xxl-5">
       {% include topbar.html lang=lang %}
-      {{ content }}
+      
+      <div class="row">
+        <main
+          aria-label="Main Content"
+          class="col-12 col-lg-11 col-xl-9 px-md-4{% unless has_tail %} pb-5{% endunless %}"
+        >
+          {{ content }}
+        </main>
+
+        <!-- panel -->
+        <aside aria-label="Panel" id="panel-wrapper" class="col-xl-3 ps-2 text-muted">
+          <div class="access">
+            {% include_cached update-list.html lang=lang %}
+            {% include_cached trending-tags.html lang=lang %}
+          </div>
+
+          {% for _include in layout.panel_includes %}
+            {% assign _include_path = _include | append: '.html' %}
+            {% include {{ _include_path }} lang=lang %}
+          {% endfor %}
+        </aside>
+      </div>
+
+      <div class="row">
+        <!-- tail -->
+        <div id="tail-wrapper" class="col-12 col-lg-11 col-xl-9 px-md-4">
+          {% if has_tail %}
+            {% for _include in layout.tail_includes %}
+              {% assign _include_path = _include | append: '.html' %}
+              {% include {{ _include_path }} lang=lang %}
+            {% endfor %}
+          {% endif %}
+
+          {% include related-posts.html lang=lang %}
+          {% include_cached footer.html lang=lang %}
+        </div>
+      </div>
+
       {% include_cached search-results.html lang=lang %}
     </div>
-  </div>
 
-  {% include_cached footer.html lang=lang %}
+  <aside aria-label="Scroll to Top">
+    <button id="back-to-top" type="button" class="btn btn-lg btn-box-shadow">
+      <i class="fas fa-angle-up"></i>
+    </button>
+  </aside>
+</div>
 
   <div id="mask"></div>
 
-  <button id="back-to-top" aria-label="back-to-top" class="btn btn-lg btn-box-shadow">
-    <i class="fas fa-angle-up"></i>
-  </button>
-
   {% if site.pwa.enabled %}
-  <div id="notification" class="toast" role="alert" aria-live="assertive" aria-atomic="true" data-bs-animation="true"
-    data-bs-autohide="false">
-    <div class="toast-header">
-      <button type="button" class="btn-close ms-auto" data-bs-dismiss="toast" aria-label="Close"></button>
-    </div>
-    <div class="toast-body text-center pt-0">
-      <p class="px-2 mb-3">{{ site.data.locales[lang].notification.update_found }}</p>
-      <button type="button" class="btn btn-primary" aria-label="Update">
-        {{ site.data.locales[lang].notification.update }}
-      </button>
-    </div>
-  </div>
+    {% include_cached notification.html lang=lang %}
   {% endif %}
 
+  <!-- JavaScripts -->
+
   {% include js-selector.html %}
 
   {% if page.mermaid %}
diff --git a/_layouts/post.html b/_layouts/post.html
index 058c77a..317b028 100644
--- a/_layouts/post.html
+++ b/_layouts/post.html
@@ -11,134 +11,133 @@ tail_includes:
 
 {% include lang.html %}
 
-<h1 data-toc-skip>{{ page.title }}</h1>
+<header>
+  <h1 data-toc-skip>{{ page.title }}</h1>
 
-<div class="post-meta text-muted">
+  <div class="post-meta text-muted">
 
-  <div class="d-flex justify-content-between">
-    <div>
-      <!-- published date -->
-      <span>
-        {{ site.data.locales[lang].post.posted }}
-        {% include datetime.html date=page.date tooltip=true lang=lang %}
-      </span>
+    <div class="d-flex justify-content-between">
+      <div>
+        <!-- published date -->
+        <span>
+          {{ site.data.locales[lang].post.posted }}
+          {% include datetime.html date=page.date tooltip=true lang=lang %}
+        </span>
 
-      <!-- lastmod date -->
-      {% if page.last_modified_at and page.last_modified_at != page.date %}
-      <span>
-        {{ site.data.locales[lang].post.updated }}
-        {% include datetime.html date=page.last_modified_at tooltip=true lang=lang %}
-      </span>
-      {% endif %}
-    </div>
-
-    <!-- post counter -->
-    <div id="likes-views">
-      {% include likes-views.html tooltip=true lang=lang %}
-      {% include comments-counter.html tooltip=true lang=lang %}
-    </div>
-
-  </div>
-
-  {% if page.image %}
-  {% capture src %}src="{{ page.image.path | default: page.image }}"{% endcapture %}
-  {% capture class %}class="preview-img{% if page.image.no_bg %}{{ ' no-bg' }}{% endif %}"{% endcapture %}
-  {% capture alt %}alt="{{ page.image.alt | xml_escape | default: "Preview Image" }}"{% endcapture %}
-
-  {% capture lqip %}
-  {% if page.image.lqip %}
-  lqip="{{ page.image.lqip }}"
-  {% endif %}
-  {% endcapture %}
-
-  <div class="mt-3 mb-3">
-    <img {{ src }} {{ class }} {{ alt }} w="1200" h="630" {{ lqip | strip }}>
-    {%- if page.image.alt -%}
-    <figcaption class="text-center pt-2 pb-2">{{ page.image.alt }}</figcaption>
-    {%- endif -%}
-  </div>
-  {% endif %}
-
-  <div class="d-flex justify-content-between">
-    <!-- author(s) -->
-    <span>
-      {% if page.author %}
-      {% assign authors = page.author %}
-      {% elsif page.authors %}
-      {% assign authors = page.authors %}
-      {% endif %}
-
-      {{ site.data.locales[lang].post.written_by }}
-
-      <em>
-        {% if authors %}
-        {% for author in authors %}
-        <a href="{{ site.data.authors[author].url }}">{{ site.data.authors[author].name }}</a>
-        {% unless forloop.last %}</em>, <em>{% endunless %}
-        {% endfor %}
-        {% else %}
-        <a href="{{ site.social.links[0] }}">{{ site.social.name }}</a>
+        <!-- lastmod date -->
+        {% if page.last_modified_at and page.last_modified_at != page.date %}
+        <span>
+          {{ site.data.locales[lang].post.updated }}
+          {% include datetime.html date=page.last_modified_at tooltip=true lang=lang %}
+        </span>
         {% endif %}
-      </em>
-    </span>
+      </div>
+
+      <!-- post counter -->
+      <div id="likes-views">
+        {% include likes-views.html tooltip=true lang=lang %}
+        {% include comments-counter.html tooltip=true lang=lang %}
+      </div>
 
-    <div>
-      <!-- read time -->
-      {% include read-time.html content=content prompt=true lang=lang %}
     </div>
 
-  </div> <!-- .d-flex -->
+    {% if page.image %}
+    {% capture src %}src="{{ page.image.path | default: page.image }}"{% endcapture %}
+    {% capture class %}class="preview-img{% if page.image.no_bg %}{{ ' no-bg' }}{% endif %}"{% endcapture %}
+    {% capture alt %}alt="{{ page.image.alt | xml_escape | default: "Preview Image" }}"{% endcapture %}
 
-</div> <!-- .post-meta -->
+    {% capture lqip %}
+    {% if page.image.lqip %}
+    lqip="{{ page.image.lqip }}"
+    {% endif %}
+    {% endcapture %}
 
-<div class="post-content">
-  {{ content }}
-</div>
+    <div class="mt-3 mb-3">
+      <img {{ src }} {{ class }} {{ alt }} w="1200" h="630" {{ lqip | strip }}>
+      {%- if page.image.alt -%}
+      <figcaption class="text-center pt-2 pb-2">{{ page.image.alt }}</figcaption>
+      {%- endif -%}
+    </div>
+    {% endif %}
 
-<div class="post-tail-wrapper text-muted">
+    <div class="d-flex justify-content-between">
+      <!-- author(s) -->
+      <span>
+        {% if page.author %}
+        {% assign authors = page.author %}
+        {% elsif page.authors %}
+        {% assign authors = page.authors %}
+        {% endif %}
 
-  <!-- categories -->
-  {% if page.categories.size > 0 %}
-  <div class="post-meta mb-3">
-    <i class="far fa-folder-open fa-fw me-1"></i>
-    {% for category in page.categories %}
-    <a href='{{ site.baseurl }}/categories/{{ category | slugify | url_encode }}/'>{{ category }}</a>
-    {%- unless forloop.last -%}, {%- endunless -%}
-    {% endfor %}
+        {{ site.data.locales[lang].post.written_by }}
+
+        <em>
+          {% if authors %}
+          {% for author in authors %}
+          <a href="{{ site.data.authors[author].url }}">{{ site.data.authors[author].name }}</a>
+          {% unless forloop.last %}{{ '</em>, <em>' }}{% endunless %}
+          {% endfor %}
+          {% else %}
+          <a href="{{ site.social.links[0] }}">{{ site.social.name }}</a>
+          {% endif %}
+        </em>
+      </span>
+
+        <!-- read time -->
+        {% include read-time.html content=content prompt=true lang=lang %}
+    </div> <!-- .d-flex -->
+
+  </div> <!-- .post-meta -->
+</header>
+
+  <div class="content">
+    {{ content }}
   </div>
-  {% endif %}
 
-  <!-- tags -->
-  {% if page.tags.size > 0 %}
-  <div class="post-tags">
-    <i class="fa fa-tags fa-fw me-1"></i>
-    {% for tag in page.tags %}
-    <a href="{{ site.baseurl }}/tags/{{ tag | slugify | url_encode }}/" class="post-tag no-text-decoration">
-      {{- tag -}}
-    </a>
-    {% endfor %}
-  </div>
-  {% endif %}
+  <div class="post-tail-wrapper text-muted">
 
-  <div class="post-tail-bottom
-    d-flex justify-content-between align-items-center mt-3 pt-5 pb-2">
-    <div class="license-wrapper">
+    <!-- categories -->
+    {% if page.categories.size > 0 %}
+    <div class="post-meta mb-3">
+      <i class="far fa-folder-open fa-fw me-1"></i>
+      {% for category in page.categories %}
+      <a href="{{ site.baseurl }}/categories/{{ category | slugify | url_encode }}/">{{ category }}</a>
+      {%- unless forloop.last -%}, {%- endunless -%}
+      {% endfor %}
+    </div>
+    {% endif %}
 
-      {% if site.data.locales[lang].copyright.license.template %}
-
-      {% capture _replacement %}
-      <a href="{{ site.data.locales[lang].copyright.license.link }}">
-        {{ site.data.locales[lang].copyright.license.name }}
+    <!-- tags -->
+    {% if page.tags.size > 0 %}
+    <div class="post-tags">
+      <i class="fa fa-tags fa-fw me-1"></i>
+      {% for tag in page.tags %}
+      <a href="{{ site.baseurl }}/tags/{{ tag | slugify | url_encode }}/" class="post-tag no-text-decoration">
+        {{- tag -}}
       </a>
-      {% endcapture %}
-
-      {{ site.data.locales[lang].copyright.license.template | replace: ':LICENSE_NAME', _replacement }}
-
-      {% endif %}
+      {% endfor %}
     </div>
+    {% endif %}
 
-    {% include post-sharing.html lang=lang %}
+    <div class="post-tail-bottom
+    d-flex justify-content-between align-items-center mt-3 pt-5 pb-2">
+      <div class="license-wrapper">
 
-  </div><!-- .post-tail-bottom -->
+        {% if site.data.locales[lang].copyright.license.template %}
 
-</div><!-- div.post-tail-wrapper -->
\ No newline at end of file
+        {% capture _replacement %}
+        <a href="{{ site.data.locales[lang].copyright.license.link }}">
+          {{ site.data.locales[lang].copyright.license.name }}
+        </a>
+        {% endcapture %}
+
+        {{ site.data.locales[lang].copyright.license.template | replace: ':LICENSE_NAME', _replacement }}
+
+        {% endif %}
+      </div>
+
+      {% include post-sharing.html lang=lang %}
+
+    </div><!-- .post-tail-bottom -->
+
+  </div><!-- div.post-tail-wrapper -->
\ No newline at end of file
