Top: part of the spectrum of one observation, with the reference line centers (from the solar line list) marked as dashed lines and the adopted line windows shown in purple. The observed line centers are slightly shifted relative to the solar reference due to differences in convective blueshift and gravitational redshift between the Sun and HD 102365. Middle: first derivative of the flux (dF/dλ), used to locate the extrema that define the window limits. Bottom: second derivative (d²F/dλ²), used to confirm the line minima (d²F/dλ² < 0). The master spectrum includes 2738 lines.