As most non-flash sites use xhtml and css only, webdesigner (or those who realize such tricky designs) must face with issues that in the end this website has to be displayed correctly — some kind of platform/browser independency. Indeed, (X)HTML is standardized by the W3C, but web-browser render websites totally differently — caused by bugs mostly (IE). This becomes quite cruical, as for ex. designs require precisely fitting their components.