html,
body,
#app {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  font: 16px "PingFang SC", "Microsoft Yahei", Arial, sans-serif;
}

#app {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

#app .downloading {
  width: 30vw;
}