Colours

CSS brings 16,777,216 colours to your disposal. They can take the form of a name, an 'rgb' (red/green/blue) value or a 'hex' code.

red
Is the same as
rgb(255,0,0)
Which is the same as
rgb(100%,0%,0%)
Which is the same as
#ff0000
Which is the same as
#f00

There are 16 valid predefined colour names. These are aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white, and yellow. 

transparent is also a valid value.