Best-fit HHeCN models to the observed MEGARA spectrum of LS 437. With a red solid line is shown the model with parameters: T_eff = 36.0 kK, log g = 3.8 dex, ξ = 11.0 km s⁻¹, Y(He) = 0.06, log (C/H) = 8.05 dex, log (N/H) = 8.10 dex. With a purple dashed line the model with parameters: T_eff = 35.0 kK, log g = 3.8 dex, ξ = 5.0 km s⁻¹, Y(He) = 0.06, log (C/H) = 7.75 dex, log(N/H) = 7.90 dex. C and N lines used in the analysis are indicated with light blue and green vertical lines, respectively. He lines are indicated with dark blue vertical lines for reference. The abundance fits were visually validated against a sensitivity margin of ±0.05 dex.