diff --git a/testing/user.js b/testing/user.js
index 8894e25..b31d938 100644
--- a/testing/user.js
+++ b/testing/user.js
@@ -1072,6 +1072,10 @@ user_pref("lightweightThemes.animation.enabled", false);
 // Enable Hardware Acceleration
 // user_pref("layers.acceleration.enabled", true);
 // user_pref("layers.acceleration.force", true);
+// -------------------------------------
+// Disable CSS-based animations and transition effects
+user_pref("layout.css.animation.enabled", false);
+user_pref("layout.css.transition.enabled", false);
 //
 // >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 // WARNINGS