Ratios between count rates in different energy bands to that of the 8–10 keV band. From top to bottom: 0.6–1 keV, 1–3 keV, 3–6 keV, and 6–8 keV. The time binning is 1128 s (~4 pulse periods), matching the spectra used in the time-resolved spectral analysis. In the background, the total flux evolution is plotted for comparison with the light curves. Circles mark the data points corresponding to the spectra shown in Fig. 5.