Iron metallicity [Fe/H] – [Mg/Fe] plane from integrated F3D spectra. Each symbol indicates the [Fe/H] and [Mg/Fe] values of one Voronoi bin within our F3D sample, color-coded by the mass of the galaxy. At fixed stellar mass, there is a clear trend where more iron-rich bins tend to be less [Mg/Fe]-enhanced. The normalization of the [Fe/H]–[Mg/Fe] relation depends on galaxy mass, with more massive galaxies showing higher [Mg/Fe] values. Light shaded lines indicate the average distribution of points for galaxies with different masses.