Results of our toy model for TNG100 galaxies with two-component dust attenuation. We show the UVJ diagram of massive, star-forming TNG100 galaxies for various combinations of the free parameters t_split and τ_V^screen in our toy model. The color-coding corresponds to the V-band attenuation for the TNG100 galaxies. We show the observational JWST/NIRCam data for massive (M_⋆ > 10¹¹ M_⊙) galaxies as grey contours. The toy model in the center of the figure with dust screns of intermediate optical depths (τ_V^screen ≈ 3.2) covering all stellar populations up to an age of t_split = 1.6 Gyr provides the best match to the observational constraints.