diff --git a/1-exercise-solutions/lesson-03/3b.html b/1-exercise-solutions/lesson-03/3b.html
index c44df60..0d4569d 100644
--- a/1-exercise-solutions/lesson-03/3b.html
+++ b/1-exercise-solutions/lesson-03/3b.html
@@ -6,6 +6,7 @@
     width: 140px;
     border-radius: 15px;
     cursor: pointer;
+    transition: background-color 0.15s;
   }
 
   .amazon-button:hover {