diff --git a/src/scriptlets/inject-css-in-shadow-dom.js b/src/scriptlets/inject-css-in-shadow-dom.js
index 7d6e824e..b927f2f2 100644
--- a/src/scriptlets/inject-css-in-shadow-dom.js
+++ b/src/scriptlets/inject-css-in-shadow-dom.js
@@ -33,9 +33,9 @@ import {
 /* eslint-enable max-len */
 
 export function injectCssInShadowDom(source, cssRule, hostSelector = '') {
-    // do nothing if browser does not support ShadowRoot
+    // do nothing if browser does not support ShadowRoot, Proxy or Reflect
     // https://developer.mozilla.org/en-US/docs/Web/API/ShadowRoot
-    if (!Element.prototype.attachShadow) {
+    if (!Element.prototype.attachShadow || typeof Proxy === 'undefined' || typeof Reflect === 'undefined') {
         return;
     }