restructuring

I have updated the Starter Kit. It now consists of three optional CSS files, which I have also uploaded individually in the downloads section.

The "Quick Start" files:

1. resets.css
       Helps to create a consistent layout across different browsers.
2. prettify.css
       Helps to create a consistent style and improves accessibility (e.g. with touch-friendly buttons and visual feedback for clickable elements).
3. forms.css
       Helps to create a responsive layout for forms.

In summary: The entire code has been restructured and is now more understandable and flexible.