drupal-vue/docroot/themes/custom/vue_js/src/components/collapsible/collapsible.scss

// Import site utilities.
@import '../../global/utils/init';

.collapsible {
  border: 1px solid black;

  &.closed {
    .body {
      display: none;
    }
  }

  .title {
    background: lightgray;

    h2 {
      margin: 0;
    }
  }
}