Flex Runtime CSS
I got a couple of questions about this at Flex Camp so I thought I'd put together a quick example of using runtime CSS. The code is pretty simple. The key is to remember that the CSS you load at runtime must be compiled into a separate SWF file; one for each style sheet.
In Flex Builder, simply right-click on your CSS file and select Compile CSS to SWF.
Also remember that when specifying the style sheet in your StyleManager.loadStyleDeclarations() call, refer to the SWF, not the CSS file.
Check out this sample. View Source is enabled. NOTE: Ignore the error and select RuntimeCSS_mxml.html to see the main source code. Source code is downloadable from the bottom-left corner of the Vew Source screen.

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