In Counter Strike: Global Offensive there are no sliders to adjust your cross hair colour. Instead you have to use a series of different console commands to get what you want. I have opted to go for the colour pink as it stands out the most on all the competitive maps.
Please note that the colour settings will only apply to the “Classic” cross hair style and not the new “Default” one that came with CS:GO.
PINK CROSS HAIR COMMANDS:
cl_crosshaircolor 5 (This tells the game you want to create a custom colour using the RGB values)
OPTIONAL CROSS HAIR SETTINGS:
cl_crosshairthickness 1 (This sets the thickness of the cross hair lines, default is 0.5)
cl_crosshairgap 0 (This sets the distance of the gap between the cross hair, default is 0)
cl_crosshairdot 1 (This adds a centre dot to the middle of the cross hair, default is 0)
cl_crosshairalpha 255 (This makes the cross hair totally solid with less transparency, default is 200)