Set background-color depending on dark/light mode

docs/conf.py

@@ -310,3 +310,4 @@ texinfo_documents = [
 def setup(app):
     app.add_js_file("js/script.js")
     app.add_css_file("css/dark.css")
+    app.add_css_file("css/light.css")

docs/resources/css/dark.css

@@ -1196,6 +1196,10 @@
         color: rgb(166, 158, 146);
     }
 
+    .wy-menu-vertical li.toctree-l3.current a {
+        background-color: #363636;
+    }
+
     .wy-menu-vertical li ul li a {
         color: rgb(208, 204, 198);
     }

docs/resources/css/light.css

@@ -0,0 +1,7 @@
+@media (prefers-color-scheme: light) {
+
+    .wy-menu-vertical li.toctree-l3.current a {
+        background-color: #c9c9c9;
+    }
+
+}