What color is Letterhead, Coop Himmelblau Architects ?

Source Crayola® CSS3 CSS4
#463e94
 
#58427c
cyber grape
#483d8b
dark slate blue
#483d8b
darkslateblue
#777686
 
#757575
sonic silver
#808080
grey
#808080
grey
#444158
 
#414a4c
outer space
#2f4f4f
dark slate gray
#2f4f4f
darkslategrey