diff --git a/core/modules/system/css/components/item-list.theme.css b/core/modules/system/css/components/item-list.theme.css
index 9a1088e..d494bf0 100644
--- a/core/modules/system/css/components/item-list.theme.css
+++ b/core/modules/system/css/components/item-list.theme.css
@@ -17,17 +17,23 @@
 [dir="rtl"] .item-list ul li {
   margin: 0 1.5em 0.25em 0;
 }
-ul.item-list__comma-list {
+ul.item-list__comma-list,
+.item-list ul.item-list__comma-list {
   display: inline;
 }
-ul.item-list__comma-list li {
+ul.item-list__comma-list li,
+.item-list ul.item-list__comma-list li {
   display: inline;
   list-style-type: none;
 }
 ul.item-list__comma-list,
 ul.item-list__comma-list li,
+.item-list .item-list__comma-list,
+.item-list .item-list__comma-list li,
 [dir="rtl"] ul.item-list__comma-list,
-[dir="rtl"] ul.item-list__comma-list li {
+[dir="rtl"] ul.item-list__comma-list li
+[dir="rtl"] .item-list .item-list__comma-list,
+[dir="rtl"] .item-list .item-list__comma-list li {
   margin: 0;
   padding: 0;
 }
diff --git a/core/themes/bartik/css/components/item-list.css b/core/themes/bartik/css/components/item-list.css
index 698bd56..eeb4e77 100644
--- a/core/themes/bartik/css/components/item-list.css
+++ b/core/themes/bartik/css/components/item-list.css
@@ -10,10 +10,3 @@
 [dir="rtl"] .item-list ul li {
   padding: 0.2em 0 0 0.5em;
 }
-.item-list .item-list__comma-list,
-.item-list .item-list__comma-list li,
-[dir="rtl"] .item-list .item-list__comma-list,
-[dir="rtl"] .item-list .item-list__comma-list li {
-  margin: 0;
-  padding: 0;
-}
diff --git a/core/themes/classy/classy.libraries.yml b/core/themes/classy/classy.libraries.yml
index a5bde77..8276033 100644
--- a/core/themes/classy/classy.libraries.yml
+++ b/core/themes/classy/classy.libraries.yml
@@ -3,6 +3,9 @@ base:
   css:
     theme:
       css/layout.css: {}
+      # We can not attach this in the item-list.html.twig template since it is
+      # often used during RendererInterface::renderPlain().
+      css/dataset/item.list.css: {}
 
 book-navigation:
   version: VERSION
diff --git a/core/themes/classy/css/dataset/item.list.css b/core/themes/classy/css/dataset/item.list.css
new file mode 100644
index 0000000..b0730d3
--- /dev/null
+++ b/core/themes/classy/css/dataset/item.list.css
@@ -0,0 +1,7 @@
+/**
+ * @file
+ * Styling for item lists.
+ */
+div.item-list__comma-list {
+  display: inline;
+}
diff --git a/core/themes/classy/templates/dataset/item-list.html.twig b/core/themes/classy/templates/dataset/item-list.html.twig
index 7ba8be4..8aa7ba9 100644
--- a/core/themes/classy/templates/dataset/item-list.html.twig
+++ b/core/themes/classy/templates/dataset/item-list.html.twig
@@ -22,7 +22,7 @@
   {% set attributes = attributes.addClass('item-list__' ~ context.list_style) %}
 {% endif %}
 {%- if items or empty -%}
-  <div class="item-list">
+  <div class="item-list {{ 'item-list__' ~ context.list_style }}">
     {%- if title is not empty -%}
       <h3>{{ title }}</h3>
     {%- endif -%}