The color expression returns a Java color, not a web-useful color (for now). What we'll probably eventually do is make the function smarter. In the meantime, you can use a transform to manipulate the color into the right format:
The color expression returns a Java color, not a web-useful color (for now). What we'll probably eventually do is make the function smarter. In the meantime, you can use a transform to manipulate the color into the right format: