diff --git a/docs/conf.py b/docs/conf.py
index 436fcdfb8..f0af548f2 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -22,6 +22,7 @@ on_rtd = os.getenv('READTHEDOCS') == 'True'
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 sys.path.insert(0, os.path.abspath('..'))
+sys.path.append(os.path.abspath('extensions'))
 
 # -- General configuration ------------------------------------------------
 
@@ -34,7 +35,8 @@ sys.path.insert(0, os.path.abspath('..'))
 extensions = [
     'sphinx.ext.autodoc',
     'sphinx.ext.extlinks',
-    'sphinxcontrib.asyncio'
+    'sphinxcontrib.asyncio',
+    'details'
 ]
 
 if on_rtd:
diff --git a/docs/extensions/details.py b/docs/extensions/details.py
new file mode 100644
index 000000000..96f39d5b6
--- /dev/null
+++ b/docs/extensions/details.py
@@ -0,0 +1,55 @@
+from docutils.parsers.rst import Directive
+from docutils.parsers.rst import states, directives
+from docutils.parsers.rst.roles import set_classes
+from docutils import nodes
+
+class details(nodes.General, nodes.Element):
+    pass
+
+class summary(nodes.General, nodes.Element):
+    pass
+
+def visit_details_node(self, node):
+    self.body.append(self.starttag(node, 'details', CLASS=node.attributes.get('class', '')))
+
+def visit_summary_node(self, node):
+    self.body.append(self.starttag(node, 'summary', CLASS=node.attributes.get('summary-class', '')))
+    self.body.append(node.rawsource)
+
+def depart_details_node(self, node):
+    self.body.append('</details>\n')
+
+def depart_summary_node(self, node):
+    self.body.append('</summary>')
+
+class DetailsDirective(Directive):
+    final_argument_whitespace = True
+    optional_arguments = 1
+
+    option_spec = {
+        'class': directives.class_option,
+        'summary-class': directives.class_option,
+    }
+
+    has_content = True
+
+    def run(self):
+        set_classes(self.options)
+        self.assert_has_content()
+
+        text = '\n'.join(self.content)
+        node = details(text, **self.options)
+
+        if self.arguments:
+            summary_node = summary(self.arguments[0], **self.options)
+            summary_node.source, summary_node.line = self.state_machine.get_source_and_line(self.lineno)
+            node += summary_node
+
+        self.state.nested_parse(self.content, self.content_offset, node)
+        return [node]
+
+def setup(app):
+    app.add_node(details, html=(visit_details_node, depart_details_node))
+    app.add_node(summary, html=(visit_summary_node, depart_summary_node))
+    app.add_directive('details', DetailsDirective)
+