diff --git a/com.unity.toonshader/Runtime/Shaders/URP/ToonURP_3Das2D.shader b/com.unity.toonshader/Runtime/Shaders/URP/ToonURP_3Das2D.shader
index b872ee783..e4c9fa555 100644
--- a/com.unity.toonshader/Runtime/Shaders/URP/ToonURP_3Das2D.shader
+++ b/com.unity.toonshader/Runtime/Shaders/URP/ToonURP_3Das2D.shader
@@ -53,7 +53,6 @@ Shader "Toon/Toon 3D as 2D (URP)"{
         _OutlineFar ("Outline Far", Float ) = 100
         _Outline_UseNormalMap ("Outline: Use Outline Normal Map", Integer ) = 0
         _Outline_NormalMap ("Outline Normal Map", 2D) = "bump" {}
-        
         [HideInInspector] _ToonMaterialVersion ("Toon Material Version", Integer ) = 0
         
     }
@@ -169,6 +168,7 @@ Shader "Toon/Toon 3D as 2D (URP)"{
 
             #include "ObjectTransform.hlsl"
             #include "ShapeLight2D.hlsl"
+            #include "../UTSLighting.hlsl"
 
             //_HDREmulationScale declaration
             #include "Packages/com.unity.render-pipelines.universal/Shaders/2D/Include/ShapeLightVariables.hlsl" 
@@ -193,31 +193,6 @@ Shader "Toon/Toon 3D as 2D (URP)"{
                 return o;
             }
 
-
-            float3 ThreeColorsLinearShading(
-                float3 baseColor,
-                float3 firstColor,
-                float3 secondColor,
-                float3  baseTo1stStart,     // t=0: use base, t=1: transition
-                float3  baseTo1stFeather,
-                float3  firstToSecondStart, //t=0: use base, t=1: transition
-                float3  firstToSecondFeather,
-                float  dotNL) // dot(N.L)
-            {
-                const float t = saturate(1 - dotNL); //t = 0: light, t=1: dark shaded
-
-                const float invBaseTo1stStart = 1 - baseTo1stStart;
-                const float invBaseTo2ndStart = 1 - firstToSecondStart;
-                
-                const float s1 = smoothstep(invBaseTo1stStart, invBaseTo1stStart + baseTo1stFeather,t); 
-                const float s2 = smoothstep(invBaseTo2ndStart, invBaseTo2ndStart + firstToSecondFeather,t); 
-                
-                float3 c01 = lerp(baseColor,firstColor,  s1);
-                float3 c12 = lerp(c01, secondColor, s2);
-                return c12;
-            }
-
-
             half4 CombinedShapeLightAndToon(ShapeLightResult shapeLightResult, SurfaceData2D surfaceData,
                 in float2 uv,
                 in float3 tangentWS, in float3 bitangentWS, in float3 normalWS, in float3 positionWS)
diff --git a/com.unity.toonshader/Runtime/Shaders/UTSLighting.hlsl b/com.unity.toonshader/Runtime/Shaders/UTSLighting.hlsl
index 5c8feb723..d62bf809b 100644
--- a/com.unity.toonshader/Runtime/Shaders/UTSLighting.hlsl
+++ b/com.unity.toonshader/Runtime/Shaders/UTSLighting.hlsl
@@ -6,4 +6,29 @@ inline float Intensity(float3 lightColor)
     return 0.299 * lightColor.r + 0.587 * lightColor.g + 0.114 * lightColor.b;
 }
 
+//----------------------------------------------------------------------------------------------------------------------
+
+float3 ThreeColorsLinearShading(
+    float3 baseColor,
+    float3 firstColor,
+    float3 secondColor,
+    float3  baseTo1stStart,     // t=0: use base, t=1: transition
+    float3  baseTo1stFeather,
+    float3  firstToSecondStart, //t=0: use base, t=1: transition
+    float3  firstToSecondFeather,
+    float  dotNL) // dot(N.L)
+{
+    const float t = saturate(1 - dotNL); //t = 0: light, t=1: dark shaded
+
+    const float invBaseTo1stStart = 1 - baseTo1stStart;
+    const float invBaseTo2ndStart = 1 - firstToSecondStart;
+                
+    const float s1 = smoothstep(invBaseTo1stStart, invBaseTo1stStart + baseTo1stFeather,t); 
+    const float s2 = smoothstep(invBaseTo2ndStart, invBaseTo2ndStart + firstToSecondFeather,t); 
+                
+    float3 c01 = lerp(baseColor,firstColor,  s1);
+    float3 c12 = lerp(c01, secondColor, s2);
+    return c12;
+}
+
 #endif // UTS_LIGHTING_INCLUDED
diff --git a/com.unity.toonshader/Runtime/UniversalRP/Shaders/UniversalToonBodyDoubleShadeWithFeather.hlsl b/com.unity.toonshader/Runtime/UniversalRP/Shaders/UniversalToonBodyDoubleShadeWithFeather.hlsl
index 8bb590c2a..7e429b3ff 100644
--- a/com.unity.toonshader/Runtime/UniversalRP/Shaders/UniversalToonBodyDoubleShadeWithFeather.hlsl
+++ b/com.unity.toonshader/Runtime/UniversalRP/Shaders/UniversalToonBodyDoubleShadeWithFeather.hlsl
@@ -1,4 +1,3 @@
-
 #include "../../Shaders/UTSLighting.hlsl"
 
 void ToonShading(
@@ -25,14 +24,21 @@ void ToonShading(
     float halfLambert = 0.5 * dot(lerp(vertexNormalWS, perturbedNormalWS, _Is_NormalMapToBase), lightDirection) + 0.5;
     
     //[TODO-sin: 2026-1-27] It looks like we only need one channel of firstShadePosTex
-    float Set_FinalShadowMask = saturate(
-        1.0 + (lerp(halfLambert, halfLambert * saturate(tweakShadows), _Set_SystemShadowsToBase)
-            - baseStepMinusFeather) * ((1.0 - firstShadePosTex.rgb).r - 1.0) / (baseColorStep - baseStepMinusFeather));
-    //
-    //Composition: 3 Basic Colors as Set_FinalBaseColor
-    float3 finalColor = lerp(Set_BaseColor, lerp(Set_1st_ShadeColor, Set_2nd_ShadeColor,
-        saturate(( 1.0 + (halfLambert - firstStepMinusFeather) * ((1.0 - secondShadePosTex.rgb).r - 1.0)
-              / (shadeColorStep - firstStepMinusFeather)))), Set_FinalShadowMask); 
+    // float Set_FinalShadowMask = saturate(
+    //     1.0 + (lerp(halfLambert, halfLambert * saturate(tweakShadows), _Set_SystemShadowsToBase)
+    //         - baseStepMinusFeather) * ((1.0 - firstShadePosTex.rgb).r - 1.0) / (baseColorStep - baseStepMinusFeather));
+
+    
+    const float dotNL = dot( perturbedNormalWS, lightDirection);
+    const float dotNL_01 = 0.5 * dotNL + 0.5;
+    float shadowFactor = lerp(1,tweakShadows,saturate(dotNL));
+    
+    float3 finalColor = ThreeColorsLinearShading(Set_BaseColor, Set_1st_ShadeColor, Set_2nd_ShadeColor, 
+        baseColorStep, _BaseShade_Feather, shadeColorStep, 
+        _1st2nd_Shades_Feather, dotNL_01 * shadowFactor);
+    
+    float Set_FinalShadowMask = dotNL_01 * shadowFactor * firstShadePosTex.r;
+///
 
     float specular = 0.5 * dot(halfDirection, lerp(vertexNormalWS, perturbedNormalWS, _Is_NormalMapToHighColor)) + 0.5;