This guy seems to be conflating design, which has principles that apply to newspapers, magazines, billboards, interactive kiosks, and web sites, with CSS, one specific technology for implementing your website's style.
No one should be worried about specific technical flaws in IE6's implementation of CSS at the same time they are worrying about how much white space they want to use in their design, whether to use a 2 or 3 column layout.
This article might have some good information here or there, but I'm not sure it is conceptually laid out well. This leads it to read more like "10 steps to a sweet web page!!!" than an introduction to design for the web.
My somewhat unoriginal advice: Read about design, decide how you want your page to look based on its contents, sketch it out, pick some colors, and THEN worry about translating it to XHTML/CSS.