They actually forgot the number one principle of clean and optimi…
They actually forgot the number one principle of clean and optimized CSS: combining commonly reused style elements. If, for instance, every div on the site will float left (they often do, if you work like I do), create a style:
div {float: left;}
instead of repeating the same style on every class and/or id. Or, if the same style is repeated on multiple classes/ids, list those classes and ids on a single style, like:
.class1, .class2, #id1, #id2 {display: block;}
That keeps the same style from showing up multiple times in the document and taking up unnecessary space.