1：App.vue中设置:

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

2：在需要设置背景图的页面设置：

#container {
  width: 100%;
  height: 100%;
  background-image: url("../assets/images/login-bg.jpg");
  background-size: cover;
  background-position: center;
  position: relative;
}