control/src/components/loading.vue

<template>
  <div class="loader" />
</template>
<style scoped>
.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;
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 22;
}

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

  100% {
    -webkit-transform: rotate(360deg);
  }
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }

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