I am unable to make up my mind here. As atlbeer says, following is the standard breakup of responsibilities: - HTML = Content - CSS = Style / Design - JS = Interaction

As argued elsewhere, lightbox straddles JS and CSS domains.

I was thinking that in CSS3 world, we should have slightly different breakup of responsibilities (subject to resolving performance issues) - HTML = Content - CSS3 = style/design and changes in style/design - JS = interaction other than purely style/design changes

I see that this breakup may lead to confusion in some situations. (Though I still find it more appealing for lightbox example) So, let me make up my mind when I have more experience with CSS3 :-)