Flash doesn’t support CSS color shorthand – an obscure feature of CSS that I bet not many know about.
CSS color shorthand defines that whenever a both hex digits in a color component of a CSS color are the same, you can eliminate one digit to reduce the color definition from 6 digits (2 each for RGB) to three digits (1 for each of RGB).
For example, white is #FFFFFF. But it can also be written as #FFF. Blue is #0000FF, but can be shortened to #00F.
Every browser seems to support this, including those based on Gecko, Webkit, Opera, and KHTML, which is really cool – CSS compressors (such as YUI Compressor) take advantage of this neat trick to knock a little off the size of a css file.
However, Adobe Flash does not support CSS shorthand color definitions. I thought Flash was supposed to be CSS compliant, so this surprised me. For example, #FFF (which should be white) shows up as a blue in Flash. Interestingly, Adobe knows about CSS color shorthand, as they discuss it in this Dreamweaver article.