Redshift evolution of the effective radius (R_e) of star-forming (blue) and quiescent (red) BGGs at fixed stellar mass M_* = 5 × 10¹⁰ M_⊙. BGGs are classified using three criteria: rest-frame NUV-r-J color (solid lines), sSFR (dashed lines), and combined color+sSFR (dotted lines). Curves show the best-fit relation R_e ∝ (1 + z)^−α, with shaded regions indicating 1σ confidence intervals. Star-forming BGGs exhibit stronger size evolution than quiescent ones in all classification schemes. The slight offset seen at z ∼ 0.6 may reflect sample scatter or minor overfitting effects in some models.