RM+CLV model from Borsa et al. (2021) as a function of phase in the planetary rest frame. The start of the transit is at the bottom; time moves vertically and is emphasised by the colour gradient. The end of the transit is indicated with a dashed, grey horizontal line. The wavelength position of the sodium doublet is indicated as dotted grey vertical lines; the centre of the high-velocity absorption components are indicated as dashed grey vertical lines.