unknown at rule @include css(unknownAtRules) error while including @include in css file

Question

I am trying to customize card columns by using Bootstrap 4 card layout. But why it is showing error if i am writing this code in my css file?

Error showing is in VS code: unknown at rule @include css(unknownatrules)

HTML file

<div class="card-columns">
  <div class="card" *ngFor="let item of vision">
    <div class="card-header">{{item.heading}}</div>
    <carousel [showIndicators]="false">
      <slide *ngFor="let item of vision">
        <img class="card-img-top embed-responsive embed-responsive-16by9" [src]="item.img" alt="vision image">
      </slide>
    </carousel>
  </div>
</div>

CSS file

.card-columns {
  @include media-breakpoint-only(md) {
    column-count: 3;
  }
  @include media-breakpoint-only(lg) {
    column-count: 4;
  }
}

Answer 1

@include is a SASS feature not CSS feature. Alternatively, you can turn the warning off by

  "css.lint.unknownAtRules": "ignore"

Reference : https://github.com/microsoft/vscode/issues/53175

https://github.com/stylelint/stylelint/issues/3190