CSS Sass Basics Improve Your Workflow with Sass Write Nested Selectors

Next, use the & symbol to create the selector .icn-success. Set the color of .icn-success to green.

Here is the appropriate code to pass this.

style.scss
.banner {
  padding: 1em;
    .icn {
        font-size: 1.25em;
    &-success {
        color: green;
}
    }
  background-color: lightgrey;
    .button {
        font-size: 1.5em;
    }

}