Getting Undefined "mixin" in sass

Hi there, I’m stuck in a project. I use sass for style sheet. main.scss is my main sass file compiled to css and it has many partials. Everything is working fine but I can’t use @mixin (_var.scss) in my partial file to @include (_about.scss). Besides I’m using @use to load other scss file


*- main.scss
|-_var.scss (@mixin is here)
|-_about.scss (I wanna load that @mixin here by @include rule).

For clarity I’m giving some screenshots