diff --git a/README.md b/README.md
index d725b8b6d0fe4cfc8dc6d27a1c9e1021d436988d..d431a4ea7211d6520f2881e9e3ead5beb7eb3778 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ You might also need to force browser to load fresh content (instead of showing a
 while reloading. Check for your browser.
 
 ## Modifying
-Learn basic html, I like to use [w3schools/html](https://www.w3schools.com/html/default.asp), and some css also covered by [w3schools/css](https://www.w3schools.com/css/default.asp). Get familiar with [w3.css](https://www.w3schools.com/w3css/default.asp).
+You need basic html, I like to use [w3schools/html](https://www.w3schools.com/html/default.asp). And basic css, also covered by [w3schools/css](https://www.w3schools.com/css/default.asp). Get familiar with [w3.css](https://www.w3schools.com/w3css/default.asp). Make sure you check your changes in different browsers, and from different platforms.
 
 ## Content
 Some of the helping files are: