Time-dependent photoionization simulations for the case of the DRW light curve. Top panel: DRW light curve. Bottom panel: Gas response at different ionization states, showing a positive response in the low-ionization state (log₁₀U = −3) and a negative response in the high-ionization state (log₁₀U = 0). In addition, in the low-ionization state the N_CIV curve appears smoother, indicating that its response timescale is longer than that in the high-ionization state.