Comparison of the spectral evolution of model ekin1p2 with a CSM (left; case mdot0p01 and rcsm6e14) and without CSM (right). The rest wavelength of the main lines is indicated and is also color-coded to differentiate different species. The lines that are affected by Doppler broadening exhibit a strong blueshift and can primarily appear in absorption (later epochs in the CSM case during the CDS phase) or primarily in emission (No-CSM case). See Sect. 5.3 for a discussion.