[inheritance] Including another class in SCSS

Try this:

  1. Create a placeholder base class (%base-class) with the common properties
  2. Extend your class (.my-base-class) with this placeholder.
  3. Now you can extend %base-class in any of your classes (e.g. .my-class).

    %base-class {
       width: 80%;
       margin-left: 10%;
       margin-right: 10%;
    }
    
    .my-base-class {
        @extend %base-class;
    }
    
    .my-class {
        @extend %base-class;
        margin-bottom: 40px;
    }