diff --git a/lib/src/visitor/serialize.dart b/lib/src/visitor/serialize.dart
index f9c468aa..021c9878 100644
--- a/lib/src/visitor/serialize.dart
+++ b/lib/src/visitor/serialize.dart
@@ -297,6 +297,11 @@ class _SerializeCssVisitor
       return;
     }
 
+    var singleton = _inspect &&
+        value.contents.length == 1 &&
+        value.separator == ListSeparator.comma;
+    if (singleton) _buffer.writeCharCode($lparen);
+
     _writeBetween(
         _inspect
             ? value.contents
@@ -311,6 +316,11 @@ class _SerializeCssVisitor
               }
             : (element) => element.accept(this));
 
+    if (singleton) {
+      _buffer.writeCharCode($comma);
+      _buffer.writeCharCode($rparen);
+    }
+
     if (value.hasBrackets) _buffer.writeCharCode($rbracket);
   }