使登录页面的内容居中

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.container {
  display: table;
  width: 100%;
  height: 100%;
}

.content {
  display: table-cell;
  text-align: center;
  vertical-align: middle;
}