diff --git a/cssmin.js b/cssmin.js
index 9838dee..d4e6d4a 100755
--- a/cssmin.js
+++ b/cssmin.js
@@ -142,7 +142,8 @@ function cssmin(css, linebreakpos) {
 
     // Put the space back in some cases, to support stuff like
     // @media screen and (-webkit-min-device-pixel-ratio:0){
-    css = css.replace(/\band\(/gi, "and (");
+    // or @supports not (display: flex)
+    css = css.replace(/([^\B:])(and|not)\(/gi, "$1$2 (");
 
 
     // Remove the spaces after the things that should not have spaces after them.