PDSs and CSs of the seven representative Insight-HXMT observations marked with vertical lines in Fig. 2, and given in Table 1. Left panels: LE 2 − 10 keV PDS (black) and HE 28 − 200 keV PDS (green). Right panels: Real (black) and imaginary (green) parts of the CS. The individual Lorentzians are shown as dash-dotted lines in the LE PDS and dashed lines in the HE PDS; in the CS, the dash-dotted lines indicate the real part, and the dashed lines indicate the imaginary part. We highlight the Type-C (red) and Type-B (blue) QPOs in the PDSs and the CSs. Data with absolute values greater than or equal to 5 × 10⁻³ are scaled logarithmically, while values with absolute values smaller than 5 × 10⁻³ are scaled linearly.