Mesh Line is obscure!

i use Mesh line Draw a grid,it is well look in Scene Window,But it is Obscure in game window[204469-屏幕截图-2023-02-05-143053.png|204469]
[204470-屏幕截图-2023-02-05-143014.png|204470]

List it up a bit. Maybe it struggles what to render first.

void Awake()
{
MeshFilter filter = gameObject.GetComponent();
var mesh = new Mesh();
var verticies = new List();

 var indicies = new List<int>();
 for (int i = 0; i < GridSize; i++)
 {
     verticies.Add(new Vector3(i, 0, 0));
     verticies.Add(new Vector3(i, 0, GridSize));

     indicies.Add(4 * i + 0);
     indicies.Add(4 * i + 1);

     verticies.Add(new Vector3(0, 0, i));
     verticies.Add(new Vector3(GridSize, 0, i));

     indicies.Add(4 * i + 2);
     indicies.Add(4 * i + 3);
 }

 mesh.vertices = verticies.ToArray();
 mesh.SetIndices(indicies.ToArray(), MeshTopology.Lines, 0);
 //mesh.RecalculateNormals();
 filter.mesh = mesh;

 MeshRenderer meshRenderer = gameObject.GetComponent<MeshRenderer>();
 //meshRenderer.material = new Material(Shader.Find("Sprites/Default"));
 //meshRenderer.material.color = Color.white;

}
}