CSS out of the markup
Linking and/or importing stylesheets would seem to be a no-brainer to the intermediate or advanced CSS developer, but I want to stress why this is so important. I’ve seen many sites start out with clean, well-organized CSS files but then get littered as time goes by, with embedded or even inline styles (due to fast updates needed on short deadlines, or possibly sometimes even pure laziness).
Imagine that you are working on an extremely large-scale website with hundreds of ways content can appear. You have fast deadlines, so you opt for making “quick fixes” or updates by using embedded or inline CSS. Years go by, and this habit continues… Until one day you’re told the site is being completely redesigned (but all the content is to remain the same), and you only have a week to build it (including testing).
Normally, this would have been a fairly simple task of updating the stylesheet(s). Except you have years worth of “quick fixes” scattered throughout the site — and no way to remember where they all are. So now you have to either a) find a way to clean everything up and get everything styled for the redesign in one week (Good luck!), or b) find a new job.
Don’t make your job harder than it really has to be. Linking and/or importing your stylesheets is not optional. Create it clean, keep it clean, and you’ll be much happier.
