Perfact the index page in demo

- only add a link to full demo.css in working example page

Some time ago, i tried to use this jquery plugin, only copied the css from the working example, and then it had some cross-browser compatibility issues on IE and Safari, which costed me a lot of time because of the keyframes and transform attribute (I don't quite understand the frontend :smile: ). 

But at last, i have found the solution has been added below the project :sob: .

So,  I think it should add a link to full demo.css file to avoid this kind of situation, juse like me :smile: .

Thanks