Mean dark matter density (upper panels) and density gradient (lower panels) profiles for halos in five mass bins, shown by the data points. The solid lines represent the best-fitting profiles using the GPR method. The gray symbols and lines show the results averaged over all directions, red for results along T₁ direction, and blue for T₃ direction. Error bars are estimated using 1000 bootstrap samples. The halo mass ranges are shown in the upper panels. The number of halos in each mass bin is shown in the corresponding upper panel. Please see Sect. 2.4 for details.