Comparison of the EUVE observation (gray line in both panels) with our models. Top panel: two models with T_eff = 70 000 K (red) and T_eff = 66 000 K (blue). Identified photospheric lines are marked at the top. Bottom panel: three models with T_eff = 70 000 K. Red, thick line: model from the top panel, red, dashed line: model with 200 times increased Ni abundance, blue, thin line: model that considered only opacities of He, C, N, O, Fe, and Ni.