I want to make grid line like this.

[![enter image description here](https://i.stack.imgur.com/ZVQa5.png)](https://i.stack.imgur.com/ZVQa5.png)

And, I made this one with wireframe.

[![enter image description here](https://i.stack.imgur.com/aM9sr.png)](https://i.stack.imgur.com/aM9sr.png)

But, I don't know how to softening the color of line gradually.

The color of the line is thinner toward the back.

What should I do?

Any help would be appreciated.