Color is the most overused tool in design.
A useful test: convert your design to grayscale. Does the hierarchy still hold? If not, you're relying on color to do work it shouldn't be doing alone.
Color should reinforce structure, not create it. Accessibility constraints (red/green colorblindness affects ~8% of men) are not just compliance — they expose where your design was leaning on color as a crutch.
See: grids-and-rhythm