diff --git a/_static/css/agaric.css b/_static/css/agaric.css
index 8810afc..95ff6f6 100644
--- a/_static/css/agaric.css
+++ b/_static/css/agaric.css
@@ -1,3 +1,7 @@
+.wy-nav-side {
+  background-color: #2f2f2f;
+}
+
 .wy-side-nav-search {
   background-color: #26599b;
 }