diff --git a/lib/helpers.js b/lib/helpers.js
index 68e45fd4..5fe25c42 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -182,10 +182,7 @@ helpers.isHyphenatedBEM = function (str) {
 };
 
 helpers.isValidHex = function (str) {
-  if (str.match(/^([A-Fa-f0-9]{6}|[A-Fa-f0-9]{3})$/)) {
-    return true;
-  }
-  return false;
+  return /^([a-f0-9]{8}|[a-f0-9]{6}|[a-f0-9]{4}|[a-f0-9]{3})$/i.test(str);
 };
 
 /**