diff --git a/core/modules/forum/css/forum.theme.css b/core/modules/forum/css/forum.theme.css
index e7490f2..21bdf4c 100644
--- a/core/modules/forum/css/forum.theme.css
+++ b/core/modules/forum/css/forum.theme.css
@@ -3,19 +3,19 @@
  * Styling for the Forum module.
  */
 
-#forum .description {
+.forum__description {
   font-size: 0.9em;
   margin: 0.5em;
 }
-#forum td.created,
-#forum td.posts,
-#forum td.topics,
-#forum td.last-reply,
-#forum td.replies,
-#forum td.pager {
+.forum__created,
+.forum__posts,
+.forum__topics,
+.forum__last-reply,
+.forum__replies,
+.forum__pager {
   white-space: nowrap;
 }
-#forum .icon{
+.forum__icon {
   background-image: url(../icons/forum-icons.png);
   background-repeat: no-repeat;
   float: left; /* LTR */
@@ -23,48 +23,35 @@
   margin: 0 9px 0 0; /* LTR */
   width: 24px;
 }
-[dir="rtl"] #forum .icon {
+[dir="rtl"] .forum__icon {
   float: right;
   margin: 0 0 0 9px;
 }
-#forum .title {
+.forum__title {
   overflow: hidden;
 }
-#forum div.indent {
+.forum .indented {
   margin-left: 20px; /* LTR */
 }
-[dir="rtl"] #forum div.indent {
+[dir="rtl"] .forum .indented {
   margin-left: 0;
   margin-right: 20px;
 }
-
-#forum .topic-status-new {
+.forum__topic-status--new {
   background-position: -24px 0;
 }
-#forum .topic-status-hot {
+.forum__topic-status--hot {
   background-position: -48px 0;
 }
-#forum .topic-status-hot-new {
+.forum__topic-status--hot-new {
   background-position: -72px 0;
 }
-#forum .topic-status-sticky {
+.forum__topic-status--sticky {
   background-position: -96px 0;
 }
-#forum .topic-status-closed {
+.forum__topic-status--closed {
   background-position: -120px 0;
 }
-
-[dir="rtl"] .forum-topic-navigation {
-  padding: 1em 3em 0 0;
-}
-[dir="rtl"] .forum-topic-navigation .topic-previous {
-  text-align: left;
-  float: right;
-}
-[dir="rtl"] .forum-topic-navigation .topic-next {
-  text-align: right;
-  float: left;
-}
-.action--forum {
+.forum__action {
   list-style: none;
-}
+}
\ No newline at end of file
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index 4ddc775..63d5369 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -483,10 +483,10 @@ function template_preprocess_forums(&$variables) {
           'data' => array(
             $topic->icon,
             array(
-              '#markup' => '<div class="title"><div>' . $topic->title_link . '</div><div>' . $topic->submitted . '</div></div>',
+              '#markup' => '<div class="forum__title"><div>' . $topic->title_link . '</div><div>' . $topic->submitted . '</div></div>',
             ),
           ),
-          'class' => array('topic'),
+          'class' => array('forum__topic'),
         );
 
         if ($topic->moved) {
@@ -503,11 +503,11 @@ function template_preprocess_forums(&$variables) {
 
           $row[] = array(
             'data' => $topic->comment_count . $new_replies,
-            'class' => array('replies'),
+            'class' => array('forum__replies'),
           );
           $row[] = array(
             'data' => $topic->last_reply,
-            'class' => array('last-reply'),
+            'class' => array('forum__last-reply'),
           );
         }
         $table['#rows'][] = $row;
diff --git a/core/modules/forum/src/Controller/ForumController.php b/core/modules/forum/src/Controller/ForumController.php
index 17c0454..c9b71b3 100644
--- a/core/modules/forum/src/Controller/ForumController.php
+++ b/core/modules/forum/src/Controller/ForumController.php
@@ -260,7 +260,7 @@ protected function buildActionLinks($vid, TermInterface $forum_term = NULL) {
     foreach ($this->fieldMap['node']['taxonomy_forums']['bundles'] as $type) {
       if ($this->nodeAccess->createAccess($type)) {
         $links[$type] = [
-          '#attributes' => ['class' => ['action--forum']],
+          '#attributes' => ['class' => ['forum__action']],
           '#theme' => 'menu_local_action',
           '#link' => [
             'title' => $this->t('Add new @node_type', [
@@ -286,7 +286,7 @@ protected function buildActionLinks($vid, TermInterface $forum_term = NULL) {
       // Anonymous user does not have access to create new topics.
       else {
         $links['login'] = [
-          '#attributes' => ['class' => ['action--forum']],
+          '#attributes' => ['class' => ['forum__action']],
           '#theme' => 'menu_local_action',
           '#link' => array(
             'title' => $this->t('Log in to post new content in the forum.'),
diff --git a/core/modules/forum/templates/forums.html.twig b/core/modules/forum/templates/forums.html.twig
index ca40e32..9bb588f 100644
--- a/core/modules/forum/templates/forums.html.twig
+++ b/core/modules/forum/templates/forums.html.twig
@@ -17,7 +17,7 @@
  */
 #}
 {% if forums_defined %}
-  <div>
+  <div class="forum">
     {{ forums }}
     {{ topics }}
     {{ topics_pager }}
diff --git a/core/themes/bartik/css/components/forum.css b/core/themes/bartik/css/components/forum.css
index 689f1d9..734ec8f 100644
--- a/core/themes/bartik/css/components/forum.css
+++ b/core/themes/bartik/css/components/forum.css
@@ -1,6 +1,6 @@
-#forum .name {
+.forum__name {
   font-size: 1.083em;
 }
-#forum .description {
+.forum__description {
   font-size: 1em;
-}
+}
\ No newline at end of file
diff --git a/core/themes/classy/templates/dataset/forum-icon.html.twig b/core/themes/classy/templates/dataset/forum-icon.html.twig
index 1e7d560..d6be503 100644
--- a/core/themes/classy/templates/dataset/forum-icon.html.twig
+++ b/core/themes/classy/templates/dataset/forum-icon.html.twig
@@ -18,8 +18,8 @@
 #}
 {%
   set classes = [
-    'icon',
-    'topic-status-' ~ icon_status,
+    'forum__icon',
+    'forum__topic-status--' ~ icon_status,
   ]
 %}
 <div{{ attributes.addClass(classes) }}>
diff --git a/core/themes/classy/templates/dataset/forum-list.html.twig b/core/themes/classy/templates/dataset/forum-list.html.twig
index 3d40b91..daf392f 100644
--- a/core/themes/classy/templates/dataset/forum-list.html.twig
+++ b/core/themes/classy/templates/dataset/forum-list.html.twig
@@ -52,26 +52,26 @@
           depth this forum resides at. This will allow us to use CSS
           left-margin for indenting.
         #}
-        {% for i in 1..forum.depth if forum.depth > 0 %}<div class="indent">{% endfor %}
-          <div class="icon forum-status-{{ forum.icon_class }}" title="{{ forum.icon_title }}">
+        {% for i in 1..forum.depth if forum.depth > 0 %}<div class="indented">{% endfor %}
+          <div class="forum__icon forum-status-{{ forum.icon_class }}" title="{{ forum.icon_title }}">
             <span class="visually-hidden">{{ forum.icon_title }}</span>
           </div>
           <div class="name"><a href="{{ forum.link }}">{{ forum.label }}</a></div>
           {% if forum.description.value %}
-            <div class="description">{{ forum.description.value }}</div>
+            <div class="forum__description">{{ forum.description.value }}</div>
           {% endif %}
         {% for i in 1..forum.depth if forum.depth > 0 %}</div>{% endfor %}
       </td>
       {% if forum.is_container == false %}
-        <td class="topics">
+        <td class="forum__topics">
           {{ forum.num_topics }}
           {% if forum.new_topics == true %}
             <br />
             <a href="{{ forum.new_url }}">{{ forum.new_text }}</a>
           {% endif %}
         </td>
-        <td class="posts">{{ forum.num_posts }}</td>
-        <td class="last-reply">{{ forum.last_reply }}</td>
+        <td class="forum__posts">{{ forum.num_posts }}</td>
+        <td class="forum__last-reply">{{ forum.last_reply }}</td>
       {% endif %}
     </tr>
   {% endfor %}
diff --git a/core/themes/classy/templates/dataset/forums.html.twig b/core/themes/classy/templates/dataset/forums.html.twig
index abf5427..eada3a8 100644
--- a/core/themes/classy/templates/dataset/forums.html.twig
+++ b/core/themes/classy/templates/dataset/forums.html.twig
@@ -15,7 +15,7 @@
  */
 #}
 {% if forums_defined %}
-  <div id="forum">
+  <div class="forum">
     {{ forums }}
     {{ topics }}
     {{ topics_pager }}