control/src/components/loading.vue

<template>
  <div class="bg">
    <div class="loader" />
  </div>
</template>
<style lang="scss" scoped>
    .bg{
        width: 100vw;
        height: 100vh;
        position: fixed;
        top: 0;
        left: 0;
        display: flex;
        align-items: center;
        justify-content: center;
        background: rgba(0, 0, 0, 0.5);
    }
    .loader {

        border: 5px solid #f3f3f3;
        border-radius: 50%;
        border-top: 5px solid #3498db;
        width: 30px;
        height: 30px;
        -webkit-animation: spin 2s linear infinite;
        animation: spin 2s linear infinite;
    }

    @-webkit-keyframes spin {
        0% { -webkit-transform: rotate(0deg); }
        100% { -webkit-transform: rotate(360deg); }
    }

    @keyframes spin {
        0% { transform: rotate(0deg); }
        100% { transform: rotate(360deg); }
    }
</style>