diff --git a/CHANGES.rst b/CHANGES.rst
index ad6d698341a..3e7ce8d8266 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,30 @@
+Release 9.2.0 (in development)
+==============================
+
+Dependencies
+------------
+
+Incompatible changes
+--------------------
+
+* #14326: The sidebar button in the classic theme has changed from a ``<div>``
+  to a ``<button>``. If you have custom styles for ``div#sidebarbutton``, you
+  may need to change the filter to ``#sidebarbutton``.
+  Patch by Hugo van Kemenade
+
+Deprecated
+----------
+
+Features added
+--------------
+
+Bugs fixed
+----------
+
+Testing
+-------
+
+
 Release 9.1.1 (in development)
 ==============================
 
diff --git a/sphinx/themes/classic/layout.html b/sphinx/themes/classic/layout.html
index d2fc9270e39..cf4ee2ebb74 100644
--- a/sphinx/themes/classic/layout.html
+++ b/sphinx/themes/classic/layout.html
@@ -9,7 +9,7 @@
 {%- endblock %}
 
 {%- block sidebarextra %}{% if theme_collapsiblesidebar|tobool %}
-<div id="sidebarbutton" title="{{ _('Collapse sidebar') }}">
+<button type="button" id="sidebarbutton" title="{{ _('Collapse sidebar') }}">
 <span>{{ '»' if theme_rightsidebar|tobool else '«' }}</span>
-</div>
+</button>
 {% endif %}{% endblock %}
diff --git a/sphinx/themes/classic/static/classic.css.jinja b/sphinx/themes/classic/static/classic.css.jinja
index 24b67fa76ed..255c8d11fed 100644
--- a/sphinx/themes/classic/static/classic.css.jinja
+++ b/sphinx/themes/classic/static/classic.css.jinja
@@ -160,10 +160,12 @@ div.sphinxsidebar input {
     background-color: {{ theme_sidebarbtncolor }};
     margin-{{side}}: 0;
     color: #FFFFFF;
+    border: none;
     border-{{side}}: 1px solid {{ theme_relbarbgcolor }};
+    font: inherit;
     font-size: 1.2em;
     cursor: pointer;
-    padding-top: 1px;
+    padding: 1px 0 0;
     float: {{ 'left' if theme_rightsidebar|tobool else 'right' }};
     display: table; /* for vertically centering the <span> */
 }
diff --git a/sphinx/themes/pyramid/static/epub.css.jinja b/sphinx/themes/pyramid/static/epub.css.jinja
index cef087ced01..a6460d4cb18 100644
--- a/sphinx/themes/pyramid/static/epub.css.jinja
+++ b/sphinx/themes/pyramid/static/epub.css.jinja
@@ -142,7 +142,7 @@ div.sphinxsidebar input {
 
 {% if theme_collapsiblesidebar|tobool %}
 /* for collapsible sidebar */
-div#sidebarbutton {
+#sidebarbutton {
     background-color: {{ theme_sidebarbtncolor }};
 }
 {% endif %}