diff --git a/index.js b/index.js
index ec4a85b..03653c7 100644
--- a/index.js
+++ b/index.js
@@ -270,7 +270,7 @@ function print_atrule(node, indent_level, css) {
 function print_prelude(node, indent_level, css) {
 	let buffer = substr(node, css)
 	return buffer
-		.replace(/([:,])/g, '$1 ') // force whitespace after colon or comma
+		.replace(/\s*([:,])/g, '$1 ') // force whitespace after colon or comma
 		.replace(/\(\s+/g, '(') // remove whitespace after (
 		.replace(/\s+\)/g, ')') // remove whitespace before )
 		.replace(/\s+/g, ' ') // collapse multiple whitespaces into one
diff --git a/test/atrules.test.js b/test/atrules.test.js
index c4d1428..abc2f6f 100644
--- a/test/atrules.test.js
+++ b/test/atrules.test.js
@@ -59,6 +59,7 @@ Atrules('AtRule prelude formatting', () => {
 		[`@media all{}`, `@media all {}`],
 		[`@media all   and print{}`, `@media all and print {}`],
 		[`@media (min-width:1000px){}`, `@media (min-width: 1000px) {}`],
+		[`@media (min-width : 1000px) {}`, `@media (min-width: 1000px) {}`],
 		[`@media all and (transform-3d) {}`, `@media all and (transform-3d) {}`],
 		[`@media all and (transform-3d), (-webkit-transform-3d) {}`, `@media all and (transform-3d), (-webkit-transform-3d) {}`],
 		[`@media screen or print {}`, `@media screen or print {}`],