:root {
  --primary-color: #409EFF;
  --success-color: #67C23A;
  --warning-color: #E6A23C;
  --danger-color: #F56C6C;
  --info-color: #909399;
}

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

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