discourse/app/assets/stylesheets/common/admin/admin_revamp.scss

.admin-revamp {
  &__config-area {
    padding: 1em;
    margin: 1em 0;
    background-color: var(--primary-very-low);
  }
}

.admin-config-area-sidebar-experiment {
  &__editor {
    margin-top: 1em;

    .ace-wrapper {
      position: relative;
      width: 100%;
      height: calc(100vh);
      min-height: 500px;
      .ace_editor {
        position: absolute;
        left: 0;
        right: 0;
        top: 0;
        bottom: 0;
      }
    }
  }
}