Total gas fraction (M_gas/M_star) plotted against the NUV-W1 (AB) magnitude (left panel) and H I fraction (M_HI/M_star) vs. NUV-W1 (right). Both magnitudes have been corrected for Galactic extinction as described in Sect. 3. The MAGMA medians are shown as a heavy gray line, and the light-gray region corresponds to ±1σ in the distributions. The contribution of H₂ to M_gas is evident in the upturn in the M_gas fraction for red NUV-W1 colors in the left panel, compared to the right.