A composite Hi-GAL color image of the infrared dark cloud. Red, green, and blue channels correspond to 350, 250, and 160 μm, respectively. To the left of the Herschel map, four NH₃ (1, 1) spectra are shown, and four selected NH₃ (2, 2) and CCS (2–1) lines are displayed on the right side of the central figure. The CCS spectra are smoothed to 0.12 km s^-1. Each row of spectra is arranged to match the black diamond markers shown on the FIR map, selected to represent typical spectra along the filament. The filament ridge, as defined in Sect. 2.1, is marked with a dashed white line.