diff --git a/CHANGES b/CHANGES
index 1143cc3b620..b787f6f94d6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -42,6 +42,8 @@ Incompatible changes
 * #8937: Use explicit title instead of <no title>
 * #8487: The :file: option for csv-table directive now recognizes an absolute
   path as a relative path from source directory
+* #9023: Change the CSS classes on :rst:role:`cpp:expr` and
+  :rst:role:`cpp:texpr`.
 
 Deprecated
 ----------
diff --git a/doc/extdev/nodes.rst b/doc/extdev/nodes.rst
index d327e1cb0c7..77872df4033 100644
--- a/doc/extdev/nodes.rst
+++ b/doc/extdev/nodes.rst
@@ -17,6 +17,7 @@ These nodes form the top-most levels of object descriptions.
 .. autoclass:: desc_signature
 .. autoclass:: desc_signature_line
 .. autoclass:: desc_content
+.. autoclass:: desc_inline
 
 Nodes for high-level structure in signatures
 ............................................
diff --git a/sphinx/addnodes.py b/sphinx/addnodes.py
index 788f9bfa25a..6b22e832adf 100644
--- a/sphinx/addnodes.py
+++ b/sphinx/addnodes.py
@@ -151,13 +151,16 @@ class desc(nodes.Admonition, nodes.Element):
     #  that forces the specification of the domain and objtyp?
 
 
-class desc_signature(nodes.Part, nodes.Inline, nodes.TextElement):
+class desc_signature(_desc_classes_injector, nodes.Part, nodes.Inline, nodes.TextElement):
     """Node for a single object signature.
 
     As default the signature is a single-line signature.
     Set ``is_multiline = True`` to describe a multi-line signature.
     In that case all child nodes must be :py:class:`desc_signature_line` nodes.
+
+    This node always has the classes ``sig`` and ``sig-object``.
     """
+    classes = ['sig', 'sig-object']
 
     @property
     def child_text_separator(self):
@@ -183,6 +186,22 @@ class desc_content(nodes.General, nodes.Element):
     Must be the last child node in a :py:class:`desc` node.
     """
 
+
+class desc_inline(_desc_classes_injector, nodes.Inline, nodes.TextElement):
+    """Node for a signature fragment in inline text.
+
+    This is for example used for roles like :rst:role:`cpp:expr`.
+
+    This node always has the classes ``sig``, ``sig-inline``,
+    and the name of the domain it belongs to.
+    """
+    classes = ['sig', 'sig-inline']
+
+    def __init__(self, domain: str, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self['classes'].append(domain)
+
+
 # Nodes for high-level structure in signatures
 ##############################################
 
@@ -507,20 +526,25 @@ class manpage(nodes.Inline, nodes.FixedTextElement):
 
 def setup(app: "Sphinx") -> Dict[str, Any]:
     app.add_node(toctree)
+
     app.add_node(desc)
     app.add_node(desc_signature)
     app.add_node(desc_signature_line)
+    app.add_node(desc_content)
+    app.add_node(desc_inline)
+
+    app.add_node(desc_name)
     app.add_node(desc_addname)
     app.add_node(desc_type)
     app.add_node(desc_returns)
-    app.add_node(desc_name)
     app.add_node(desc_parameterlist)
     app.add_node(desc_parameter)
     app.add_node(desc_optional)
     app.add_node(desc_annotation)
-    app.add_node(desc_content)
+
     for n in SIG_ELEMENTS:
         app.add_node(n)
+
     app.add_node(versionmodified)
     app.add_node(seealso)
     app.add_node(productionlist)
diff --git a/sphinx/domains/cpp.py b/sphinx/domains/cpp.py
index a54b110c33f..d56ade684ba 100644
--- a/sphinx/domains/cpp.py
+++ b/sphinx/domains/cpp.py
@@ -7394,11 +7394,9 @@ def __init__(self, asCode: bool) -> None:
         if asCode:
             # render the expression as inline code
             self.class_type = 'cpp-expr'
-            self.node_type = nodes.literal  # type: Type[TextElement]
         else:
             # render the expression as inline text
             self.class_type = 'cpp-texpr'
-            self.node_type = nodes.inline
 
     def run(self) -> Tuple[List[Node], List[system_message]]:
         text = self.text.replace('\n', ' ')
@@ -7406,20 +7404,19 @@ def run(self) -> Tuple[List[Node], List[system_message]]:
                                   location=self.get_source_info(),
                                   config=self.config)
         # attempt to mimic XRefRole classes, except that...
-        classes = ['xref', 'cpp', self.class_type]
         try:
             ast = parser.parse_expression()
         except DefinitionError as ex:
             logger.warning('Unparseable C++ expression: %r\n%s', text, ex,
                            location=self.get_source_info())
             # see below
-            return [self.node_type(text, text, classes=classes)], []
+            return [addnodes.desc_inline('cpp', text, text, classes=[self.class_type])], []
         parentSymbol = self.env.temp_data.get('cpp:parent_symbol', None)
         if parentSymbol is None:
             parentSymbol = self.env.domaindata['cpp']['root_symbol']
         # ...most if not all of these classes should really apply to the individual references,
         # not the container node
-        signode = self.node_type(classes=classes)
+        signode = addnodes.desc_inline('cpp', classes=[self.class_type])
         ast.describe_signature(signode, 'markType', self.env, parentSymbol)
         return [signode], []
 
diff --git a/sphinx/themes/basic/static/basic.css_t b/sphinx/themes/basic/static/basic.css_t
index f809d0eb450..45404529119 100644
--- a/sphinx/themes/basic/static/basic.css_t
+++ b/sphinx/themes/basic/static/basic.css_t
@@ -527,6 +527,10 @@ table.hlist td {
 	font-style: italic;
 }
 
+.sig-inline.cpp-expr {
+	font-family: monospace;
+}
+
 
 /* -- other body styles ----------------------------------------------------- */
 
diff --git a/sphinx/writers/html5.py b/sphinx/writers/html5.py
index 3b2523fddb8..3bd48e558a6 100644
--- a/sphinx/writers/html5.py
+++ b/sphinx/writers/html5.py
@@ -117,6 +117,12 @@ def visit_desc_content(self, node: Element) -> None:
     def depart_desc_content(self, node: Element) -> None:
         self.body.append('</dd>')
 
+    def visit_desc_inline(self, node: Element) -> None:
+        self.body.append(self.starttag(node, 'span', ''))
+
+    def depart_desc_inline(self, node: Element) -> None:
+        self.body.append('</span>')
+
     # Nodes for high-level structure in signatures
     ##############################################