Empty Site with: import "@ionic/core/css/ionic.bundle.css";

Hello,

why is my testpage empty when i use:
import “@ionic/core/css/ionic.bundle.css”;

Thank you

Here is the code

import Vue from “vue”;
import App from “./App.vue”;
import router from “./router”;
import Ionic from “@ionic/vue”;
//here is the problem; i get an empty site when import “@ionic/core/css/ionic.bundle.css”;
import “@ionic/core/css/ionic.bundle.css”;
Vue.config.productionTip = false;

new Vue({
router,
render: h => h(App)
}).$mount("#app");