CSS Shorthand question

Hi all
For shorthand with css colours I know I can change #ffffff to #fff (all the letters are the same) and it works fine but can I change
#E1E1E1 to #E1E1 or even #E1? Thanks

Short answer, no.

Long answer:

The format of an RGB value in hexadecimal notation is a ‘#’ immediately followed by either three or six hexadecimal characters. The three-digit RGB notation (#rgb) is converted into six-digit form (#rrggbb) by replicating digits, not by adding zeros. For example, #fb0 expands to #ffbb00. This ensures that white (#ffffff) can be specified with the short notation (#fff) and removes any dependencies on the color depth of the display.

That comes from http://www.w3.org/TR/CSS2/syndata.html#value-def-color

Hope that helps.

Thanks