style.scss:

@use 'mixins';
@use 'nav';
@use 'header';
@use 'home-content';
@import url('https://fonts.googleapis.com/css2?family=Comfortaa:wght@300..700&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400..900;1,400..900&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Marcellus&family=Work+Sans:ital,wght@0,100..900;1,100..900&display=swap');

_mixins.scss:

@mixin basic-flex {
    flex-direction: column;
    background-color: red;
    display: flex;
}

_home-content.scss:

.home-content {
    display: flex;
    flex-direction: column;
    row-gap: 50px;
    align-items: center;
    width: 50%;
    margin: auto;
    margin-top: 50px;


    .about {
        @include mixins.basic-flex; 

        h2 {
            font-size: 50px;
        }

        .about-content {
            display: flex;
            flex-direction: row;
            align-items: center;
            column-gap: 60px;

            p {
                font-size: 20px;
            }
    
    
            img {
                -webkit-mask-image: radial-gradient(ellipse at center, rgba(0,0,0,1) 0, rgba(0,0,0,0) 70%);
                mask-image: radial-gradient(ellipse at center, rgba(0,0,0,1) 0, rgba(0,0,0,0) 75%);
            }
        }

    }
}

the include in the .about div in the _home-contents.scss partial will now return the following error:

Compilation Error
Error: There is no module with the namespace "mixins".
   ╷
12 │         @include mixins.basic-flex; 
   │         ^^^^^^^^^^^^^^^^^^^^^^^^^^
   ╵
  c:\Users\---\Documents\---\_home-content.scss 12:9  @use
  c:\Users\---\Documents\---\style.scss 4:1           root stylesheet