diff --git a/modules/nixos-wiki/default.nix b/modules/nixos-wiki/default.nix
index 1c78b51..1407552 100644
--- a/modules/nixos-wiki/default.nix
+++ b/modules/nixos-wiki/default.nix
@@ -177,6 +177,9 @@ in
 
         # Block spam by regex
         $wgSpamRegex = ["/seo (software|tools)|adult toys|pornstars|casino|gambling|viagra/i"];
+
+        # Allow user-defined CSS for experimentation
+        $wgAllowUserCss = true;
       '';
     };