modify README

Author: geckotang

README.md

@@ -1,7 +1,11 @@
 # CSS PANIC
 
-No JS! Pure HTML/CSS Game.
-
 ![playing image](img.gif)
 
--> [PLAY NOW](https://geckotang.github.io/csspanic/) <-
+[PLAY!](https://geckotang.github.io/csspanic/)
+
+No JS! HTML and CSS only.
+
+This code was born in 2012.
+
+The original is http://jsdo.it/GeckoTang/4rXg however the service is often down. So the code is moved at [CodePen](https://codepen.io/geckotang/pen/wLXZvr) & [GitHub](https://github.com/geckotang/csspanic)