Duplicate (Ctrl d) the square and lines.

Select the square and modify the two colors using the RGB colors shown here.

NOTE: We will be using RGB color values from here on out so be sure to select the RGB Color Model option in the Color Editor.

Change the line colors using these two colors.

Make another duplicate of the lines and background square. Apply these two values to the background square.

Change the color of the lines using these two values. Remember the lighter value is on top.