You're probably here because you've purchased a copy of the book, and would now like to download the chapters' example code. If so, you're in the right place.
Inside the .zip you'll find a directory for each chapter. In each chapter's directory in the finished example that relates to the example. All of the CSS was placed in the
<head> of the document for simplicity. These files should give you an even better understanding of how each bulletproofed method was ultimately put together, and allow you to experiment with the code on your own.
Thanks for picking up a copy of Bulletproof Web Design!