Influence of viscosity on the evolution of the planetary system for α_v = 10⁻⁶,10⁻⁵,10⁻⁴, and 10⁻³, where 10⁻⁵ represents our fiducial model. The figure displays the semi-major axes, the period ratio of planets, and the eccentricity of inner and outer planets from top to bottom. The first row is divided into right and left panels, illustrating the semi-major axes of the inner and outer planets, respectively.