Nicolas Chevallier 03 January 2010 Thanks for this article. I agree about creating a prototype directly in HTML to speed up prototyping and save time skipping the transformation from proto to HTML. I have some questions about using all these CSS3 features, specially box-shadow and rgba in terms of performance : have you ever tested performance about paint reflow? What is the cost using these? Negligible? I wonder that if you have a background image with a rgba box over it for example.