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A Flash of unstyled content (FOUC) is an instance where a web page appears briefly unstyled prior to loading an external CSS stylesheet, due to the web browser engine rendering the page before all information is retrieved. The page corrects itself as quickly as the style rules are loaded and applied; however, the shift is quite visible and distracting. After the web page appears, the viewer sees unstyled HTML morph into a differently styled document.
The aberration, called FOUC, was documented and named circa 2001 in an article at [http://bluerobot.com/web/css/fouc.asp/ BlueRobot.com]. A...