What color is Book Cover, The New Science ?

Source Crayola® CSS3 CSS4
#4b643f
 
#414a4c
outer space
#556b2f
dark olive green
#556b2f
darkolivegreen
#2f332a
 
#414a4c
outer space
#2f4f4f
dark slate gray
#2f4f4f
darkslategrey
#d7dbcc
 
#dbd7d2
timberwolf
#d3d3d3
light gray
#d3d3d3
lightgrey