Unfolded energy spectra of MAXI J0903–531 in different states. The luminosity varies by a factor of ~30 (panel a). The black, red, and blue points correspond to the Swift/XRT, NuSTAR, and SRG/ART-XC data, respectively. Data from two NuSTAR modules are combined for illustrative purposes only. The dashed lines represent the best-fitting models listed in Table 3. The corresponding residuals for the low- and high-luminosity states of MAXI J0903–531 are presented in panels b and c, respectively.