change backdrop color

Author: yairhaimo

introjs.min.css

@@ -63,7 +63,7 @@
 }
 
 .intro-backdrop {
-    background: rgba(0, 0, 0, 0.2);
+    background: rgba(255, 255, 255, 0.6);
     position: fixed;
     left: 0;
     top: 0;