In a typical workday, I deal with dozens of yahoo stores and very often I have to tweak, fix, or change CSS used by these stores. While some stores have very clean and easy to follow style sheets or CSS definitions, the vast majority of stores I've seen seem to include complete hack jobs, style sheets put together completely haphazardly, or as an afterthought. While working in such a store, the idea came to me to turn my gripes into a post. So the following is my list of dos and don'ts of good CSS or style design. 1. Externalize your style sheets. This means to save your style sheets into one or more css files, and link to them using the <link rel="stylesheet" type="text/css" href="/lib/yourstoreid/yourstyle.css"> notation, or in Editor V3.0, you can use the LINK operator. 2. Combine your style sheets into as few files as possible. Nothing worse than trying to wade through 6, 8, 10 or more different style sheets to find the color of a l