Constant border width in shader, ignore view distance

I have a 2d mesh (all vertices` z coordinate is 0). I use mesh normals to create line border. So every normal is looking inside the mesh. Shader use 2 passes. On first pass full mesh is drawn in black. Then I draw inner mesh on the second pass. It looks fine but when i scale line width is scaling as well but I want it to be constant. What I want is to make line constant width. I tried using fwidth but get no results. Here is shader code

 Shader "Custom/Outline" {
     Properties
     {
         _Color("Color", Color) = (1, 1, 1, 1)
         _OutlineExtrusion("Outline Extrusion", float) = 0
     }
 
     SubShader
     {    
         //inner polygon
         Pass
         {                            
             Blend SrcAlpha OneMinusSrcAlpha      
             Stencil
             {
                 Ref 4
                 Pass replace
             }
 
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
 
             // Properties
             uniform float _OutlineExtrusion;
 
             struct vertexInput
             {
                 float4 vertex : POSITION;
                 float3 normal : NORMAL;
                 float4 color : COLOR;
             };
 
             struct vertexOutput
             {
                 float4 pos : SV_POSITION;
                 float4 color : COLOR;
             };
 
             vertexOutput vert(vertexInput input)
             {
                 vertexOutput output;
 
                 float4 newPos = input.vertex;
 
                 float3 normal = normalize(input.normal);
                 newPos += float4(normal, 0.0) * _OutlineExtrusion;
 
                 output.pos = UnityObjectToClipPos(newPos);
 
                 output.color = input.color;
 
                 return output;
             }
 
             float4 frag(vertexOutput input) : COLOR
             {
                 return input.color;
             }
 
             ENDCG
         }
 
         //bigger polygon
         Pass
         {
             Stencil
             {
                 Ref 4
                 Comp notequal
             }
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
 
             float4 _Color;
 
             struct vertexInput
             {
                 float4 vertex : POSITION;
             };
 
             struct vertexOutput
             {
                 float4 pos : SV_POSITION;
             };
 
             vertexOutput vert(vertexInput input)
             {
                 vertexOutput output;
 
                 output.pos = UnityObjectToClipPos(input.vertex);
 
                 return output;
             }
 
             float4 frag(vertexOutput input) : COLOR
             {
                 return _Color;
             }
 
             ENDCG
         }
         
     }
 }