When someone makes the inevitable switch from internet explorer to Mozilla Firefox, Chrome, etc. they will immediately understand the fact that not all browsers are created equal. Not only are the features and ease of use different from browser to browser, but the actual look of a website can change depending on what you’re using. This may seem overwhelming, but there are a few steps you can take to make a website appear as similar as possible across different browers.
Color is pretty much impossible to keep exactly the same from one computer to another because of the different graphic cards and drivers in each computer, so don’t pull your hair out trying to make them look exactly the same. It’s not going to happen. Sorry. When it comes to deciding which color group to use, first figure out what the output will be. If the output will be on a computer monitor then RGB is the way to go. If the piece will be printed, CMYK is usually the standard and the best option.
The second step you can take to save yourself a Tylenol bottle worth of headaches is to test, test, test. And maybe test some more. Techradar has an excellent blog post detailing the tools that are out there for html and css testing which can be found here. Also a great way to find potential problems in your code is http://validator.w3.org , but keep in mind that not everything it finds is necessarily a problem and that every problem will not necessarily show up.
Another great tutorial that I found useful was an article by Sascha P. Corti on browser and feature detection. It goes much deeper into technical aspects then I have here and has some excellent advice.