Difference in colour between nucleus and its host galaxy as a function of the host galaxy stellar mass. We show both g′−r′ (pink) and g′−i′ (gold) colours based on the multi-component decomposition models. The moving averages were calculated using a bin width of 2 dex and moved in steps of 0.2 dex. The shaded regions denote the SEM. The marker size denotes the nucleus contrast. The uncertainties were estimated by propagating the nuclei colour uncertainties (see Appendix D) and the galaxy colour uncertainties calculated in Su et al. (2021; see their Table 1).