A hex colour such as #FCFCFC consists of three pairs representing RGB. The second part of each pair can be reduced to darken any colour without altering the colour considerably.
eg. to darken #FCFCFC, lower the values of C to give #F0F0F0
Reducing the first part of each pair by a small amount will also darken the colour, but you will start to affect the colour more (eg. turning a green to a blue).
