Is there a W3 or any other noteworthy standard on how to represent a color (including alpha channel) in hex format?
Is it #RGBA or #ARGB?
It looks like there is no hex alpha format: http://www.w3.org/TR/css3-color/
Anyway, if you use a CSS preprocessor like SASS then you can pass an hex to rgba
:
background:
rgba(#000, 0.5);
And the preprocessor just converts the hex code to rgb automatically.