AThe color value must begin with the hash or pound sign (#). Omitting the # is a common cause of errors.
BYou can use six-digit or three-digit hexadecimal values
CThe letter A-F in a hexadecimal value are case-insensitive. It doesn't matter whether you use uppercase or lowercase, or even a mixture of the two.
DYou must use six-digit hexadecimal values
EThe color value can begin with the hash (#) sign but it is optional.