Good design and good markup provide structure to content. Good markup is a fundamental part of good design: beautiful on the inside, beautiful on the outside. HTML and CSS give another venue to provide structure to content in the native language of the web, and learning these guides decisions by surfacing the affordances of the medium. Design decisions are affected by both the content and the format, like how a sculptor would make different decisions if she were working with clay rather than marble.
via via Frank : Designers vs Coding.
