UV-optical slope (S) as a function of the mass-weighted stellar age (⟨a⟩_*^m. Gray stars represent individual S measurements from our sample, with 1σ uncertainties derived through a bootstrapping method. Black stars indicate the median S values for galaxies grouped by ⟨a⟩_*^m, and the error bars show the 1σ dispersion within each bin. The solid cyan line represents the best-fit correlation for the entire sample using a power-law model (Eq. 4), and the shaded regions indicate the uncertainty ranges. Literature results for intermediate-z sources or stacks are illustrated as green (Shivaei et al. 2020a; Battisti et al. 2022) and teal (Álvarez-Márquez et al. 2019) symbols. Finally, high-z objects (Markov et al. 2023; Ormerod et al. 2025) are depicted as orange and red symbols, respectively. The error bars represent their 1σ uncertainties.