silverstripe-webpack/app/client/src/scss/_cms.scss

@import "~@a2nt/ss-bootstrap-ui-webpack-boilerplate/src/scss/types/cms";

.notifications-list {
  .alert {
    .btn-close {
      display: none;
    }
  }
}

.btn-outline-primary,
.btn-primary {
  color: #fff;
}